"Eureka!" Moment

Yup. Criminals are the superstitious ones.

Wilson: I've just given you the answer, haven't I? And now you're going to walk out of here without saying a word.
House: [walking out the door] Nope.

— House, episode "Joy"

All complex problems are solved by sudden epiphany!

In every Locked Room Mystery, the detective can't solve the crime just by examining the relevant evidence. They always need some external inspiration (apparently) completely unrelated to everything, something along the lines of:

Sharona: Oh well, looks like you don't solve the crime. Whatever. Let's go get milkshakes.
Monk: Milkshakes… The killer is lactose intolerant. So is the victim's ex-wife! Of course!!

…or…

Bob: No tea, please.
Dave: That's how that letter found its way twenty miles to a dead man in Sudbury!

Can take the form of a Flashback-Montage Realization and will lead directly to The Summation, unless there's an Evidence Scavenger Hunt in between. Often the character having the epiphany will tell the person whose offhand remark inspired it that they're "a genius" or the like; the remarker will then variously nod in a befuddled manner, ask "I'm what?", or simply demand an explanation. A character who wants clarification about what they just heard will often ask the other person to Repeat What You Just Said.

Named for perhaps the most famous non-detective related example, Archimedes' exclamation of "Eureka!" after jumping into a bath and realizing that held the key to the problem he was trying to solve. (See below for details.)

The Eureka Moment shows up a lot on diagnosis-mystery medical shows, such as House, in which he does it in nearly every episode, and in the first episode of Grey's Anatomy, which isn't even a medical detective show! It may also show up on telenovelas or soap operas with some ongoing secret that defines a character or even the main plot. The truth is often almost revealed several times, by easily overheard conversations or weak evidence, and each time the status quo is kept with some contrived explanation. When the Eureka Moment takes place, The Reveal is not the result of a confession or an evidence that is too solid to be ignored, but instead the result of the hero putting all the small hints together and figuring out the truth by himself. In this case, expect a wave of several flashbacks of those hints before the "Eureka!".

Not to be confused with a Bat Deduction. While both can initially appear almost identical, a Eureka Moment leads to a coherent chain of reasoning that the detective can explain to the bystanders later; whereas a Bat Deduction, if it gets explained at all, makes even less sense after the explanation. However, although logically sound, the Eureka Moment may be enough to convince the one who came to it, but not to convince others (specially a court of law). In this case, the character may began a quest to obtain a Smoking Gun to prove things beyond any reasonable doubt.

Often used as a Deus ex Machina, albeit one that is acceptable more often than annoying. If the detective actually takes the idea literally rather than using it as an inspiration, that is I Was Just Joking. Can even happen in your sleep, with Dreaming the Truth.

Compare Luck-Based Search Technique and You Were Trying Too Hard. See Placebo Eureka Moment for when there wasn't any external inspiration, but they act like there was, and Love Epiphany, when the insight gained is that one party loves the other. See also Explain, Explain... Oh, Crap! for a similar situation where instead of finding a solution, someone becomes aware of a problem.

May contain unmarked spoilers.

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Examples:

Advertising

• A commercial for Shell gasoline shows a scientist trying to figure out how to explore for petroleum reserves underwater without building multiple derricks and drilling dozens of holes. While at a restaurant with his son, his son uses a bendy-straw upside down to suck up the last bits of milkshake at the very bottom of the glass, causing an epiphany. Cue the scientist making a pitch for a "bendy-drill" design.
• Breakstone's cottage cheese had two:
  • One has Paul Breakstone sitting in a bathtub while wondering how to make his cottage cheese more practical. Meanwhile, his wife is yelling at him that his bath time is over. Just before the commercial ends, his wife walks by and says "Get out of that tub!" He then gets the idea to package the cottage cheese in individual cups.
  • Another has him sitting under a peach tree, wondering what he can put in his cheese so kids would eat it. "Maybe something sweet," he says, as peaches start to fall around him. Then he exclaims, "I've got it! Pineapple!" (He may have Failed a Spot Check there, but th completed product has both peach and pineapple varieties.)
• In an 80s commercial for Lucky Charms, Lucky was pondering what new marshmallow shape to add to his cereal, when an angry purple horse kicked him in the butt; he quickly thought of Purple Horseshoes. ("Eh, the idea just hit me!" he told the kids, while rubbing his behind.)

Anime & Manga

• Case Closed does this a lot.
  • One time, Conan solved a murder he had been stuck on just by Ran mentioning that she had bought new pajamas for them. (To be more specific, she mentioned that said PJs were a matched pair, leading Conan to realize that the murderer was a set of identical twins.)
  • Conan is a brilliant detective hiding in the body of a small child, so if he figures something out before anyone else, it's not uncommon for him to subtly lead those around him to their own Eureka Moment, rather than raising suspicions about himself by voicing his deductions directly.
  • There is also a certain part wherein Heiji and Conan figures out the dying message, but start, at Heiji's prompting, to subtly lead Kazuha to deciphering the dying message to make her feel better, as she was about to cry.
  • As well as Conan deliberately inducing Eureka moments to Kogoro due to Kogoro's It's Personal attitude after the murder of one of his old judo teammates.
• Once per Episode in Vicky the Viking, Vicky and his crew of Vikings will be stuck in some terrible dilemma. Vicky will rub his nose for a bit, then inspiration for the resolution will strike.
• In an episode of Cardcaptor Sakura, wherein two of her magical allies were cursed with Shapeshifter Mode Lock and could not effectively masquerade as non-magical, she had no idea how to break the spell until she was given a dead crab as a gift. She was inspired by the crab's shell which protects it "just like a shield!" and deduced that she could use her Shield card to protect her allies from the curse's outside interference long enough for them to transform.
  • This was also how she first defeated the Watery card. As she was at the aquarium with Yukito, she stares at his ice drink for a bit...then realizes that, since Watery is water, it can be stopped by freezing it.
• In Utawarerumono (the visual novel), Hakuoro studies a strand of Mutikapa's fur in frustration, unable to explain why the creature fled the previous night when it had him and Eruruw in its grasp. Unable, that is, until Eruruw drenches him and the fur in tea and this trope ensues.
• Arguably the entire point of Yakitate!! Japan, but applied to making bread. For example, one of these moments leads to the creation of Kazuma's "sushi-style" melon bread.
• In Magic Kaito, another work by author Gosho Aoyama (author of the aforementioned Case Closed), Kaito figures out how an old, poor magician got a parliamentary pen after a kidnapper claiming to be the Kaitou Kid took the Prime Minister after Aoko tells him the key to beating the boss of their video game is to defeat the king controlling him first.
• Pokémon: The Series:
  • Ash Ketchum has one of these in pretty much every Gym battle to turn it around (granted, his epiphanies don't always make the most sense). If you see him panicking because his opponent is pulling some kind of unbeatable schtick, then snap his head up with a thousand-yard stare and say "wait, that's it!", chances are someone's about to get their ass beat.
  • Sometimes his companions do it too. May and Dawn get a few of these during their contest battles.
  • Invoked by Cameron by snapping his headband back if he's in a pinch during a Pokemon battle. It doesn't always work though.
• Togusa gets two of these moments, early in the first season of Ghost in the Shell: Stand Alone Complex, and in both of them, he's in a bathroom, looking at the mirror. In the second, the mirror is crucial: He realizes that, from the batch of pictures he's examining, all of them show a mirror or other reflective surface, but the camera isn't visible in any of them.
  • In fact, this is basically his main schtick. It's one of the reasons he's one of Section 9's most effective members; he's really good at putting the pieces together.
• Occurs in Patlabor The Movie. Our heroes are trying to find out what's causing some Humongous Mecha with a new OS to go out of control. While taking a break while the investigation seems to be leading nowhere, Noah sees a dog barking at something they can't see & mentions they can hear things humans can't, cluing Shinohara in to the fact that ultrasonic waves are the culprit.
  • Shinohara actually gets two of these in the film. The second comes when they learn that the evil genius who created the program had a plan to make all the robots in Tokyo to go crazy at once & are trying to figure out what could cause enough ultrasonic waves to make it happen. When a whistling tea kettle causes a nearby figurine in a glass case to shake they realize it's sympathetic vibrations in skyscrapers caused by the wind. Fortunately, it'd take a mind-bogglingly huge building & incredibly powerful winds for a city-wide disaster to occur. Unfortunately a giant factory complex has just finished construction in Tokyo Bay & a record-breaking typhoon is due to hit in three days…
• Naru has these regularly in Ghost Hunt, usually due to an offhand comment from Mai.
• Similar to Ash Ketchum above, Yugi Muto from Yu-Gi-Oh! gets these when he realizes how to beat an opponent's seemingly unbeatable combo. One of his most triumphant examples is when he figures out how to defeat Slifer the Sky Dragon.
• Happens to Misawa in Yu-Gi-Oh! GX as a way to break himself out of the resident cult's More than Mind Control. It's also a Shout-Out to Archimedes' original eureka moment, so keep the Brain Bleach handy. (The dub edited in a pair of underpants.)
• Happens twice in Fullmetal Alchemist, within the same scene. When trying to decipher a code from Scar's brother's notes, the group takes a break to reassemble Al who is in pieces, like a puzzle. May rips the bindings of the notes and with Scar and Marcoh's help reassemble it to see the nationwide transmutation circle (which Ed and Al figured out beforehand). When trying to think there was a silver lining in this, Yoki sneezes and causes the papers to shift. They're annoyed that the papers have been 'flipped over', and Al comes to his realization that the papers needed to be turned over to see the other half of the hidden message: a second transmutation circle which can be used to reverse the effects of the first.
• Vegeta gets one during the final battle against Buu in Dragon Ball Z. When Goku doesn't have the energy to push the Spirit Bomb to destroy Buu, Vegeta tries to get Mr. Satan to talk the people of Earth into giving more energy, and Mr. Satan refuses, because it would probably kill them (as they had already donated their energy to form the Spirit Bomb in the first place). Vegeta angrily points out that if it wasn't for his plan to use the Namekian Dragon Balls to wish back Earth and its people, they'd all still be dead... and then Vegeta realizes that they still have a wish left, which they use to restore Goku's energy.
• Naruto has more than a few of these when trying to learn new jutsus.
  • When learning the Rasengan's rotation step, which involves bursting a water balloon, he struggles with getting the water to rotate in the desired fashion until he happens upon a cat batting one of his water balloons around. He gets the idea of using his other hand to start the rotation, and quickly masters the step.
  • When Naruto's learning the Rasenshuriken, an advanced form of the Rasengan that also involves adding wind element chakra into the Rasengan, Naruto, who already needs a Shadow Clone to handle the "control" step of the Rasengan, complains that adding the wind chakra is like looking left and right at the same time. Kakashi then summons a Shadow Clone to show Naruto how he can do that, inspiring Naruto to add an additional clone to do just that.
  • Late in Naruto's Sage Mode training, Naruto, struggling with how to use sage chakra in battle when he has to sit still in order to gather it, hears the previous "look left and right" phrase again, and comes up with the plan to have a Shadow Clone gather sage chakra.
• Double Subverted during the Culture festival arc of Kaguya-sama: Love Is War when a Phantom Thief steals all the extra heart shaped balloons class 2-B had and then leaves behind a clue to their next target that has a bunch of clock faces on it. Fujiwara seemingly sovles it when Erika makes a comment about the sun setting earlier in the winter (making her come to the conclusion that the different times on the clocks corrospond to timezones). When she runs off to the computer lab for further information, Kaguya mentions to Hayasaka that Fujiwara was probably just making stuff up, but a comment that she made about how "all mysteries exist to be solved" caused her to figure out the actual answer. Namely that there isn't one. Shirogane just threw a bunch of meaningless symbols together to keep the riddle loving Fujiwara distracted so she wouldn't interfere with his Grand Romantic Gesture to Kaguya.
• In Super Cub, Koguma is busy trying to find a cheap way of protecting her eyes, since she can't afford a helmet with a face shield, when she sees a man cleaning her school's library with a protective face mask and goggles. She then realizes goggles are a cheap but practical solution.
• In the éX-Driver film, after they are captured on Wang Somin's orders, Angela Gambino tells Souichi Sugano that she rigged a car to crash when they first met and later made an exploding AI cleaning car severely damage the track, all in an effort to ultimately stop her father Rico from gambling on the race.
• In Mister Ajikko, whenever Yoichi is unsure about what to do to solve his culinary problems at hand, expect him to encounter something seemingly unrelated that will inspire and lead him to a needed solution soon afterwards.
• In The Kindaichi Case Files, whenever Kindaichi feels stuck trying to deduce a murder plot, something seemingly unrelated soon jolts him into the realization that will help him to solve the case at hand.

Comic Books

• Art Ops: The Body has one from seeing Juliet eat a peanut butter and jelly sandwhich. Thinking of how the two complement each other, it leads him to realise that the best way to track down the Mona Lisa is to release Bruno, the Mona Lisa's own Foil.
• Batman's Eureka Moment from way, way back in Detective Comics #27 defined his career:
  Bruce Wayne: Criminals are a superstitious cowardly lot. So my disguise must be able to strike terror into their hearts. I must be a creature of the night, black, terrible…
  [window blows open, and a certain species winged mammal flies in]
  Bruce: A BAT!
• Berrybrook Middle School:
  • After some words from Ms. Tobins, Peppi gets the idea to unite the Art and Science clubs through a project that combines their talents.
  • In "Brave", after Jensen says that Akilah and Jenny's fight was a lizard brain moment, the former realizes that he's absolutely right, and she finds it in herself to both make amends (though it's mostly Jenny who apologizes) and help get Felicity out of suspension.
• Parodied in a "how to draw the characters" variant cover for Daredevil:
  1. A lot of comic artists use photo reference when drawing! So, for this one, pull up an image of someone who resembles Daredevil, like popular New York District Attorney Matt Murdock!
  2. Use a light blue pencil to rough out the shape of his head and placement of features. Ha! Just noticed that Murdock wears red glasses!
  3. As most of you know, Matt Murdock is blind, so he may not even realize that Daredevil's main color of choice is red! Anyway! Sketch out the rest of his features!
  4. Now, with a darker pencil, use the blue template to sketch out the shape of Daredevil's head, and give him some eyes! How does he see through those tiny red lenses! Ha ha!
  5. Okay! Now you can add all the details that make him Daredevil! I mean, makes the HEAD Daredevil, not Murdock! Though Murdock does have a great knowledge of the law and criminals, and being blind in public would really throw people off your-
  6. Oh my god
• Disney Ducks Comic Universe: In one Gyro Gearloose story, the Beagle Boys steal Gyro's thinking cap (a device that he needs to come up with great ideas) and threaten to destroy it unless Gyro builds them special gear to help them with heists. Helpless, Gyro is forced to comply and while the Beagles go on a crime spree, laments that he can't come up with a brilliant idea to stop the crooks. This gets him thinking- Does the idea have to be brilliant? After all, fancy tools or not, the Beagle Boys are the same greedy thugs they've always been. He defeats the Beagles by creating a knockout gas bomb disguised as a diamond, and simply waits for the Beagles to steal it.
• Evil characters also can have this, as Iznogoud proves:
  Iznogoud: Do you have an idea how I could get rid of the Caliph, Wa'at Alahf?
  Wa'at Alahf: Sir, I'd rather feed my tongue to a cat!
  Iznogoud: [thinking] Tongue to a cat... the cat is a predator... the tiger is also a predator... the tiger is a man-eater... the Caliph is a man... so the tiger is a Caliph-eater!
  Iznogoud: [aloud] That's a great idea of you, organizing a tiger hunt!
  Wa'at Alahf: A tiger hunt? Me? What?
• Used in the Origins Episode story for Grant Morrison's JLA. Starro has taken over a tower filled with people along with The Flash (Wally West). A temporary team, comprised of the rest of Morrison's first line up — Superman, Batman, Wonder Woman, Aquaman, Martian Manhunter and Green Lantern (Kyle Rayner) — have gathered, only for The Spectre to step in and tell them "no". After being shown a Bad Future, Batman decides to go in alone. When the Spectre isn't stopping Batman, Spectre points out that Batman is only human, that Starro is aiming for metahumans. Superman realizes that the answer is right there and asks Spectre to strip them of their powers so they can aid Batman.
• At the end of The Fall and Rise of Vandal Savage story arc of Justice Society of America Classified, Vandal Savage is at his lowest point. He's dying of a brain tumor, all of his resources are gone, and he just failed to kill Alan Scott whom he sees as an embodiment of "The Green", a bogeyman of death that has haunted Vandal Savage throughout his long life. He bitterly realizes that Alan Scott will outlive him. The disfigured clone Vandal Savage made of himself as part of his failed scheme then asks him if there's anything he can do to make Savage comfortable and addresses him as "father". Vandal Savage pauses then asks the clone to repeat what he just called him. The clone calls him father again. This leads to Vandal realizing that the clone is technically a descendant of his, and since Vandal's immortality is rejuvenated by eating the flesh of his descendants...
• In The Legend of Zelda: A Link to the Past (1992), a librarian gets the idea for a hot air balloon from a boy who draws an analogy to his bubble bath.
• In almost every issue of The Maze Agency, some seemingly random comment or event will start the gears spinning in Gabe's head and cause him to suddenly see the solution to the current mystery.
• Pacific Rim: Tales from Year Zero: Lampshaded. Naomi asks Dr. Jasper Schoenfeld, who helped develop the Jaegers, to recount the development of technology. She refers to the anecdotal story that he got the idea to build giant robots to fight the Kaiju when watching his son play with action figures as his "famous Eureka moment".
• A flashback in Rat Queens shows Violet condemned to a miserable life of fulfilling family obligations. Then she meets Morgan who has escaped by just ignoring the obligations. Shortly afterward Violet does the same.
• In one issue of The Amazing Spider-Man, Reed Richards and Iron Man have literally minutes to defuse a bomb left by Doctor Octopus that would destroy New York City, while the rest of the Fantastic Four and The Avengers look on. Johnny Storm suggests that Spider-Man could come up with a "fallback plan", prompting Spider-Man to point at a clock reading nearly 2 am, saying "There's no time for me to come up with a fallback… fall back… THAT'S IT!" He then syncs the bomb's electronic timer with its main OS system's internal clock. Turns out it was the first Sunday in November, meaning the end of Daylight Savings Time, when people set their clocks back an hour or "Fall back". By syncing the bomb's timer, Spider-Man was able to extend the countdown by an hour, giving the FF and the Avengers enough time to take the bombs out to sea to explode harmlessly.
  • Ultimate Spider-Man: Kong (who up until now has been the Dumb Muscle school bully) remembers several things: the incident with Peter Parker and the weird spider at Oscorp, that Pete suddenly became a great basketball player, that he broke Flash's hand, that Spider-Man debuted at the wrestling club shortly after the gang visited it, that Spider-Man showed up to save the school when the Green Goblin began to attack it...and Kong suddenly realizes Peter Parker is Spider-Man! Being Kong, his response to this is to then run through the school yelling this to the world.
• Supergod. Reddin has a literal one while sitting on the toilet, foreshadowing that it's a really crap idea, given that his idea causes The End of the World as We Know It.
• In Superman: Space Age, Flash's ship-in-a-bottle gift gives Superman the idea to use Kryptonian crystals as an ark for humanity.
• In one Star Wars Legends comic, Darth Vader has been able to torture out the means of hunting down the Rebel Alliance's hyperdrive paths and sought to capture prisoners to find the Rebel Fleet, but kept getting stopped by the targets being obliterated. After the second target was destroyed, Vader attempted to Force Choke the General in anger, who refused to apologize for what happened, stating he was inspired by the Empire's destruction of Alderaan. Through the Force, Vader realizes they're being played and set up a test with a certain gunner at a place claimed to be a Rebel Base, which he destroyed. Vader ended up setting it up as a Batman Gambit: had the gunner not been the sabotaur, the base would have suffered minimal damage. If he was, then, as he learns to his horror, he just destroyed one of the last surviving colonies of Alderaan, his homeworld.

Comic Strips

• The Far Side; one cartoon shows Albert Einstein having written and crossed out on a blackboard "E=mc^3", "E=mc^4", and many other variations with the number different. He notices the cleaning lady who has just straightened out his desk saying, "There we go, everything squared away. Squaaaared away."

Fan Works

• In All Mixed Up!, Oscar, feeling frustrated after spending half a week trying to figure out why agents are turning into various objects, lashes out, remarking on how he and Otto are getting nowhere and how things get "all mixed up" no matter what they do. This allows Otto to figure out that the culprit is turning everyone into objects that are anagrams of their titles and names.
• Calvin & Hobbes: The Series has at least one of these, when Calvin becomes The Insomniac and tries to get to sleep, an inquiry regarding stopping all noise prompts Hobbes to use the Time Pauser.
• In The Chronicles of Merlin: The Return Dumbledore and Fudge battle over custody of Harry, who wants neither of them to win. When Ron comments that they'll probably be fighting over it for weeks, Harry realizes that if he gets other people to join in, they'll all be so busy fighting that nobody will get custody of him, buying him some time.
• Dirty Sympathy: Apollo realizes that his bracelet helps him pinpoint lies when it reacts when Klavier says he can handle Daryan but it doesn't when Apollo goads him into admitting that he hates Daryan and would rather be with Apollo.
• In Earth and Sky, Twilight first starts working on how to help non-pegasus ponies fly after her conversations with Pinkie and Pumpkin, but doesn't settle on the idea of using artificial wings until she sees Sweetie Belle wearing a pair as part of her Princess Celestia costume.
• In The Egg Team, Eggman suddenly comes up with the idea of using Mobians to fight against Sonic and his friends while repairing Metal Sonic, who had been recently defeated.
• Reimu experiences one of these in Fantasy of Utter Ridiculousness. When Coop is able to attack both Yuuka and her clone in the midst of a Double Spark, she has a flashback to the events of Imperishable Night and the teamwork needed to resolve the incident... and it's there that she's finally able to figure out how to get everyone out of the fight alive.
• Fallen King has this. Joey and Tristan ramble about The Wizard of Oz and wanting to fly home like Dorothy, and suddenly remember Kaiba's helicopter.
• Fashion Upgrade (Miraculous Ladybug):
  • Marinette decides the theme for the fashion show will be the temporary heroes of Paris after she prevents Chat Noir from falling off her couch and he thanks her calling her "his hero".
  • Discussed. When asked how she came up with the idea of making Mayura the main character in the class play, which allows it to fit the chosen theme without hitting Paris’s Hawk Moth-shaped Trauma Button, Rose credits “a visit from inspiration.” “Inspiration” more frequently goes by the name Marinette Dupain-Cheng, but Rose can’t admit this because the class isn’t supposed to have outside help or discuss the details of their project with others.
• Graduate Meeting of Mutual Killing: Trial 2. The surviving characters need to find a culprit candidate besides Hikasa, the one that's already under suspicion, and the Mastermind, a former suspect. However, there's almost no evidence that could point towards anybody else. Toriumi has spent the whole trial forcing people to throw a ball around in what she said was "a way to keep hands nimble and our minds even more nimble". Then Ogata realizes the true purpose of this ruse: to find who among the survivors is left-handed, as only a left-handed person could have killed the victim the way it happened, without alerting the culprit. And how did it result? It succeeded.
• In chapter 1 of Harry's Loophole, during Ron and Harry's first argument concerning Harry's name coming out of the Goblet of Fire, Ron accidentally gives Harry the idea to only show up to the events but not try; It'll be competing, but without the danger. Another positive is that hearing Harry proclaim that he's gonna go with his idea convinces Ron that Harry didn't put his name in and that he's not a glory hound, thus averting their months-lasting fight.
• In chapter 41 of Harry Potter And The Rune Stone Path, Luna translates Hermione's Magi Babble into Layman's Terms as they explain to the extra credit Defense Against the Dark Arts class why the shield spell absorbs some spells and reflects others. Harry Potter overhears while he's trying to figure out why his runic cluster isn't absorbing the pieces of Voldemort's soul.
  Harry [thinking]: Incompatible energies… absorption vs. banishment… Souls can't be absorbed… souls can't be absorbed!
  [Harry erases the Absorption rune and replaces it with a Banishment rune]
  Harry [shouting]: Haha! Got it! Take that you bloody thing! Who's the runemaster now, huh!
• In the Horseshoes and Hand Grenades story, SplitxEnd, Yayoi figures out how Gentaro was resurrected from the dead after seeing her best friend JK being possessed by Ryutaros and having to beat him up with a pillow.
  • In A Month of Sundays, Akiko as Kamen Rider Skull makes a comment about Shotaro not knowing about justice that makes Jun solve everything regarding Damballa's Carnival of the Human Spirit act clear.
• Infinity Train: Blossoming Trail
  • When Chloe struggles to figure out what her story is going to be about, having been hit with writer's block for three days, describes this as constantly chasing after something...and then creates a story that is basically a Revenge Fic on how she hates Goh chasing after Mew.
  • The chapter later when Chloe is praised by Titus for having figured out the answer to his question — "What does she have in common to previous passengers" — she says that forgiving Lexi (For having lashed out at his father and getting Chloe hot water burns when trying to stop the fight) wasn't that big a deal. She realizes that the answer to the question is that all passengers had the potential to change for the better.
  • An even bigger moment happens when Atticus wishes to know about the tales of Pokémon in Chloe's world. Chloe realizes that even if she doesn't like being a Professor or Trainer, she could still be involved with the monsters in some way by researching the numerous legends and myths surrounding them.
• In Kyon: Big Damn Hero, Mikuru realizes a loophole to allow a time traveler change history without violating causality after commenting to Kyon that the dinner she just cooked was "add[ing] some things from outside of the normal recipe".
• Chapter 4 of Lucky At Cards: Cordelia learns that a spell was cast on her as a child to manipulate events so as to ensure she stays a virgin. That causes her to realize she should have stayed together with Xander. She dumped him on Valentine's Day in front of everyone right after he gave her a beautiful gift, all with some flimsy excuse about Harmony. Under normal circumstances, she'd have spent the night riding him like a rented mule but she broke up with him instead.
• In Mall Rats, a fanfiction of The Loud House, Lincoln is impatient with Leni rejecting all his shoe choices, but when he complains to himself that she's "turning them down flat", he gets an idea about wearing the top she rejected with a pair of flats and wearing the heels she rejected earlier with a romper.
• Naru-Hina Chronicles: Shizune needs to find someone who can be a messenger in charge of running important messages between Konoha and Suna, or else she'll have to do that job herself. She asks Naruto if he's willing to do that, but he declines, much to her disappointment. Naruto then wishes he knew someone who wanted to go to Suna alone, only to immediately realize that Shikamaru might be that person. The latter accepts the job, as it will allow him to spend more time with Temari, although Naruto never even thought about that and only assumed Shikamaru would accept it just because he doesn't mind being by himself and the job requires little work.
• The Ouroboros: April, like the rest of her companions, is puzzled about how the Stable Time Loop they're supposedly enacting is meant to work, especially since their future counterparts have refused to offer any real explanations, citing 'spoilers'. Things click into place when she overhears a sulking Leo, sore over Donnie's teasing about how he's Not So Above It All, grumbles "No wonder our future selves don't want us to come home." This causes her to realize that their counterparts lied — they really don't want them to come home. Ever.
• Rosario Vampire: Brightest Darkness: In Act III chapter 42, with the revelation that Fairy Tale is still active and coming to attack Yokai Academy, Tsukune remarks to Moka that Akua and Kahlua said that Fairy Tale had been destroyed. At that very moment, Moka recalls the mystery vampire agent they fought in Ashton City during Act II, and from the evidence she failed to notice before (namely the agent's fighting style, voice over the radio, knowledge of Moka, and the fact that Akua just suddenly showed up right after they left Ashton City), realizes that Akua was said vampire agent; thus, Akua and Kahlua have been working for Fairy Tale all along.
• In A Taste of the Good Life, Scootaloo comments that when she was out on her own she would have tried to sneak into restaurants for scraps. "Heck, I would have eaten the empty bowls if I could have." This gives Main Course the idea of making edible soup bowls out of bread rolls.
• In This Bites!, during the Thriller Bark arc, the crew ends up dealing with Moria who had Awakened his Devil Fruit powers, leading Su to snark that Soundbite was as helpless as the rest of them even though he's on the same level. This causes Soundbite to snap and go into a rant that he's still a snail and his powers still have limits, and that Awakened abilities take god-tier amounts of energy to use, topped off by saying even Moria's pushing it since he just Awakened, and that even if he had ten times his normal energy, Soundbite wouldn't be able to use as much power as Moria's using for ten minutes without burning out. Upon reaching those last two words, Cross and Soundbite realize how to defeat him.
  Cross: (high-eying Soundbite) And that is why we stick together!
  Soundbite: That and you wipe my ass!
• Bakugo in Waiting is worth it figured out that Izuku's step-father Toshinori was All Might on his own simply from observation.
• In We Can Do This Forever, Starlight Glimmer issues the titular statement during her battle across time with Twilight Sparkle, causing Twilight to realize how she can eventually defeat Starlight. As The Ageless, Twilight literally can fight Starlight forever, whereas Starlight will eventually grow old and die.
• In Winds of Change Neville mentions how Harry's presence always made Hogwarts seem more homelike, leading Harry to the conclusion that a depressed, divorced Fleur needs to go home to France.

Films — Animation

• In 101 Dalmatians II: Patch's London Adventure Patch is blue screening after his Broken Pedestal for Thunderbolt when one of his siblings references an episode of Thunderbolt's show where Thunderbolt escaped a cage like the ones they're trapped in, misidentifying the number. Patch dully corrects them before realizing that he can use his memories of the show to get out of his cage.
• In The Adventures of Ichabod and Mr. Toad, during the Sleepy Hollow segment, Brom Bones is stewing on his Comically Lopsided Rivalry with Ichabod Crane when he spots Ichabod spill salt, then desperately throws some over his shoulder. Brom's expression goes from shocked to conniving as he clearly realizes he can use Ichabod's superstitious nature to his advantage.
  Narrator: ...And Brom knew there was no more firm, potent believer in spooks and goblins than Ichabod Crane.
• In The Adventures of Tintin (2011), Tintin is about ready to call it quits after the bad guys get away and Captain Haddock gives him a "You Are Better Than You Think You Are" speech about not letting failure get to him. It's this speech that gives Tintin an idea about how they can catch up with the bad guys.
  Tintin: You can call me what you like. Don't you get it? We failed.
  Haddock: Failed. There are plenty of others willing to call you a failure. A fool. A loser. A hopeless souse. Don't you ever say it of yourself. You send out the wrong signal, that is what people pick up. Don't you understand? You care about something, you fight for it. You hit a wall, you push through it. There's something you need to know about failure, Tintin. You can never let it defeat you.
  Tintin: What did you say earlier?
  Haddock: You hit a wall, you push through it.
  Tintin: No, something about sending a signal… [has an epiphany and reacts with a clap] Of course! Captain, I sent a message on the Karaboudjan! I know what frequency they're on!
• In Aladdin, Aladdin is fighting Jafar but making no headway. A taunt from the sorcerer gives Aladdin the answer he needs to win; playing Jafar's ego power-lust by calling him second best to the Genie.
  Jafar: Without the Genie, boy, you're nothing!
  Aladdin: The Genie...(Inspired) The Genie! (To Jafar) The Genie has more power than you'll ever have!
• In The Bad Guys (2022), Mr. Wolf and Diane are trying to figure out Marmalade's plot. Diane pulls up a heat map of the city, showing large herds of guinea pigs all over Los Angeles, but moving without an obvious target. Mr. Wolf notices the map on his copy of the charity gala program with each of the charities marked on it, and they realize it's moving targets: Marmalade is after the armored trucks carrying the one billion dollars of charity money.
• Batman Beyond: Return of the Joker:
  • When Terry tries to piece everything together, he first tries to reassure Bruce that he's got what it takes to fight him, saying "I'm a different Batman. I was never a Robin, I never…", when he realizes that while the Joker wrecked the Batcave, the Robin suit was the only one of the old suits which was singled out in being destroyed, which is what makes Terry deduce that the Joker is really the possessed Tim Drake.
  • The key moment where Terry realizes there's a different path to beating the Joker is when he asks Bruce for advice, and realizes that his particular style is one the Joker never faced... especially in the psychological department. This is what lets him turn the fight around by proceeding to wear the Joker down through well-aimed taunts.
    Terry: He's tough… any suggestions, boss?
    Bruce: Joker's vain, and likes to talk. He'll try to distract you, but don't listen! Block it out and power on through!
    Terry: …Wait. I like to talk, too.
• Beauty and the Beast: Gaston is inspired by the townsfolk's mockery of "crazy old Maurice" in order to blackmail Belle into marrying him.
• A Bug's Life: Princess Atta thanks Flik for saving her sister Dot from the sparrow, stating it was very brave, adding that even the genuinely terrifying Hopper is terrified of birds. Which gives Flik the ingenious idea of building a bird decoy to scare off Hopper.
  Princess Atta: Not every bug would face a bird. I mean, even Hopper's afraid of 'em.
  Flik: Yeah, well you know it was— [beat] Say that again.
  Princess Atta: I said, even Hopper's afraid of birds.
  [Flik sprints off, then sprints back to Atta and kisses her cheek]
  Flik: Thank you. [sprints off again]
• Coco: Mamá Coco goes through one near the end of the film as Miguel sings "Remember Me" for her, restoring her memory and remembering her father Héctor.
• Frozen: Anna's Heroic Sacrifice and subsequent Disney Death near the end of the movie causes Elsa to have an epiphany as to what "True love can thaw a frozen heart" means, allowing her to gain full control over her powers and stop the endless winter threatening to freeze Arrendelle. Moreover, it's thanks to Olaf describing what true love means ("thinking of other's needs before your own") that subsequently brings Anna out to see Kristoff which then segues into the Heroic Sacrifice and Disney Death.
• The Great Mouse Detective:
  • When Ratigan realizes Basil is following Fidget to his lair, he growls "Oh, I can just see that insufferable grin on his smug face…" Then Ratigan grins evilly as he gets the idea to prepare an ambush, and says "Yes…I can just see it…"
  • Dawson struggles to snap Basil out of a Heroic BSoD while the two are stuck in Ratigan's death trap, then eventually snaps "If you've given up, we might as well set it off now and be done with it!" This gives Basil the idea to set the trap off early at just the right moment in order to not only escape certain death, but free himself, Dawson, and Olivia.
    Basil: Set it off…now? Yes…yes, that's it! We'll set the trap off now!
• How to Train Your Dragon: When Hiccup is bring grilled by Stock about his secret friendship with a dragon, he accidentally lets slip that Toothless took him to island containing the dragons' nest and that only a dragon knows where it is, which gives Stoick the idea to bound Toothless to his ship and force him to lead the tribe to it.
• Inside Out has Joy breaking down and crying over Riley's forgotten memories, and one of the tears lands on a happy memory of Riley's hockey team cheering for her. Joy wipes away the tear, rewinding the memory and turning it sad, as she is sitting on a tree looking depressed because she missed the winning shot, losing the game. Joy fast forwards the memory slowly which shows Riley's mom and dad comforting her on the branch, followed by the team, which turns it happy again. Joy realizes how Sadness can lead to happy memories, and the role that Sadness plays in Riley's mind: "Mom and Dad... the team... they came to help because of Sadness."
• The Iron Giant:
  • As Agent Kent Mansley leaves the Hughes after borrowing their phone, he remarks about Hogarth's name, which leads him to…
    Kent Mansley: "Hogarth?" That's an embarrassing name. They might as well have called him "Zeppo" or something. What kinda sick person would name their kid "Hogar…? [stops and looks over to Hogarth's smashed B-B gun which Kent found at the power station; it reads part of Hogarth's name: Hog- Hug] "Hog Hug?" HOG HUG? HOGARTH HUGHES!!! [screeches his car to a stop]
  • Dean has one after Hogarth takes off after the Giant, who runs away after nearly blasting the kid with his Eye Beams. When Dean notices Hogarth’s toy gun on the ground, he realizes that the Giant has an automatic self-defense mechanism.
    Dean: It was defensive. He reacted to the gun!
• Justice League X RWBY: Super Heroes and Huntsmen:
  • When Superman watches Ruby rescue Flash from being crushed by the Wyvern, Superman suddenly remembers the last part of their fight back on Earth, which involves Kilg%re capturing Flash in his hand. With this memory and noticing Flash hasn't been helpful during the fight with the Grimm, he confronts Flash to get answers from him, but more Grimm conveniently suddenly start attacking before they could talk.
  • When Kilg%re reveals themself and that they were the ones to capture the League, Ruby points out that they also caught Team RWBY and JNR and that part of the plan doesn’t make sense. It makes Batman realize they had help.
• Kung Fu Panda:
  • Po has one of these after learning the secret ingredient to his father's secret ingredient soup. There is no secret ingredient. It's this knowledge that allows him to understand the wisdom of the Dragon Scroll.
  • Shifu has an earlier one; Tai Lung is coming, and Po has proven to be completely inept at learning martial arts. He then sees Po perform athletic feats in order to get some Comfort Food, and realizes that he can use this fact to train him.
    Po: [up in the ceiling, doing a perfect split to hold himself up while eating cookies] No, this? …This is just an…accident.
    Shifu: ...There are no accidents.
• The LEGO Movie:
  • While escaping the Old West, the wheel to Emmet, Wyldstyle, and Vitruvius' carriage gets shot off and Vitruvius suggests to Emmet they should attach the wheel to something that spins around. When Emmet rotates his head in complete circles struggling to find something, he gets the idea to attach the wheel to his head and use his body as a wheel well.
  • After Emmet performs a Heroic Sacrifice to save the Master Builders, they struggle to find hope with him gone, with MetalBeard bemoaning "If only there were more people in the world like he...". Wyldstyle looks upon the citizens of Bricksburg and gets the idea to convince them to fight back against Lord Business and his forces.
• Meet the Robinsons: Lewis is surrounded on all sides in the middle of a Bad Future brought about by an invention his future self will create. He complains to himself, "Why did I invent that stupid hat!?" which gives him the idea to Set Right What Once Went Wrong by swearing to never create the evil hat.
• Monsters, Inc.:
  • Mike and Sulley try to escape from Randall and Mike says that they'll start a new life far away, shouting "Goodbye, Monsters Inc.! Goodbye, Mr. Waternoose!". This gets Sulley the idea to tell Waternoose about Randall's plot and hopefully solve the dilemma. That turned out to be a big mistake, as Randall is working for Mister Waternoose on the "scream extractor" project.
  • At the end of the movie Mike, realizing that in getting the Big Bad arrested they've gotten the factory closed, put hundreds of monsters out of work and made the energy crisis worse, tries to downgrade the events by saying, "But hey! At least we got a few laughs, right?" This causes Sully to make the connection that the energy produced by a child's laughter is ten times more powerful than the energy produced by their screams.
• Monsters University: Chet tells Mike that some monsters aren't cut out for the big leagues. "Big leagues" inspires Mike to go on a little "field trip".
• "Jack's Obsession" from The Nightmare Before Christmas leads up to an Eureka Moment, with Jack even shouting "EUREKA!!!"
• Patlabor: The Movie: Asuma figures out Hoba's plan is to use resonance between the Ark and Tokyo's buildings to make Labors go berserk across Tokyo after the whistling from a teakettle makes a glass cabinet door in Shige's apartment rattle.
• Peter Pan:
  • After Smee tells Captain Hook about how Tinker Bell got banished after she almost got Wendy killed out of jealousy, Hook gets the idea to prey on her emotions to get her to reveal the location of Peter's hideout.
    Hook: Did you say Pan has banished Tinker Bell?
    Smee: Aye-aye, Cap'n. That he has.
    Hook: But why?
    Smee: On account of Wendy, Cap'n. Tink tried to do her in, she did. Tink's terrible jealous.
    Hook: Well, well...
    Smee: And that's why we ought to leave, Cap'n. This ain't no place for a respectable pirate.
    Hook: That's it, Smee! THAT'S IT!
  • Hook later fakes one as part of his act to trick Tinker Bell by offering to help her get rid of Wendy.
    Hook: But we mustn't judge Peter to harshly, my dear. It's that Wendy who's to blame! Mr. Smee, we must save the lad from himself! But how? We've so little time. We sail in the morning. ...Sail! That's it, Smee! We'll shanghai Wendy!
    Smee: Shanghai Wendy, Cap'n?
    Hook: Take her to sea with us! With her gone, Peter will soon forget this mad infatuation!
• In Pinocchio, just when Pinocchio and Gepetto think they'll never escape Monstro the whale, Gepetto says that they should forget it and start a fire to cook some fish. This gives Pinocchio the idea to start a fire that will make Monstro sneeze them out.
• In Robin Hood (1973), Sir Hiss tells Prince John that Friar Tuck is in the jail, and P.J. is initially furious that it wasn't Robin Hood until the realizes that he can use the Friar as bait to trap Robin and then hang them both.
• The Rugrats Movie: When Chaz & Howard notice baby footprints and wheel tracks in the woods, the adults realize the kids are in the woods, on the Reptar Wagon. When Drew angrily calls Stu out on this, it gives Stu the idea to search for the kids on his Dactar Glider.
  Stu: They must be in my Reptar Wagon!
  Drew: "It's the perfect children's toy!" You and your stupid inventions!
  Stu: My stupid inventions... That's IT!
• In Shark Tale: When Oscar decides to save Angie from the mob, Lenny lets it slip to Sykes that Oscar is a phony. Sykes is horrified to discover this (earlier, Sykes joyfully told Lino, the head shark, to shut up), and begs Oscar to say he is a real Sharkslayer. Oscar admits he isn't, then realizes that the sharks don't know he's a fraud and gets the idea to keep his charade long enough to rescue Angie.
  Sykes: Tell me you didn't make the whole thing up! T-T-Tell me that's not Lenny! Tell me you're a real Sharkslayer! PLEASE!
  Oscar: I'm sorry, Sykes. I'm not. (his eyes widen in realization) But the sharks don't know that.
• At the end of Space Jam, Swackhammer is laying into the Mon-Stars for losing the game. Michael asks them why they take so much abuse from him and they respond that it's because Swackhammer is bigger...than they used to be. After this revelation, they send Swackhammer packing.
• Tangled:
  • When Rapunzel and Flynn are trapped in a dark cave filling rapidly with water and need light to see by, this exchange occurs:
    Flynn: My real name is Eugene Fitzherbert. I figured someone should know.
    Rapunzel: I have magic hair that glows when I sing — I HAVE MAGIC HAIR THAT GLOWS WHEN I SING!
  • Near the end of the movie, Rapunzel realizes who she really is when she sees the royal symbol for Corona subconsciously hidden in her murals. "I'm the lost princess…"
• In Toy Story 2, Buzz is trying to figure out who stole Woody with only a Vanity License Plate to go by; LZTYBRN. The other toys are dismissive of this, and Mr. Potato Head just says, "Let's leave Buzz to his toys." This makes Buzz realize that the kidnapper is the Al from Al's Toy Barn, especially when they make Etch-a-sketch do a composite of the suspect in a chicken suit (which he found out when he picked up a feather that came out of Al's trunk Buzz was chasing his car earlier).
• In Turning Red, Mei and her friends get the idea to hustle Mei's panda form after Stacy Frick says she'll give them anything for experiencing more of her panda form including money.
• In Wreck-It Ralph:
  • Ralph realizes who Vanellope really is when he sees the Sugar Rush video game and discovers her picture on the console.
  • Vanellope gets her own when she sees Ralph hammering away at a seemingly indestructible Jawbreaker. The second she mentions it's indestructible, Ralph splits it in half, and Vanellope's eyes light up as she gets the idea to get Ralph's help in breaking into the cart factory to make her a race car.
• Zootopia:
  • Nick gets the idea to check the traffic cams after spilling some of his backstory to Judy and trying to Change the Uncomfortable Subject.
  • When Nick and Judy look at the traffic cam footage to find where Manchas was taken, the scene of the timber wolves howling leads her to conclude that Mr. Otterton's phrase "Night Howlers" was in reference to them.
  • When Judy is in Bunnyburrow during her 10-Minute Retirement, she finally learns what the Night Howlers really are from overhearing Gideon Grey talking with her parents.
    Judy: Night Howlers aren't wolves…they're flowers. The flowers are making the predators go savage! That's it! That's what I've been missing!

Films — Live-Action

• Played with in π. Mathematician Max consults with his mentor Sol about a numerical sequence he's trying to solve. Sol tells him the story about Archimedes (see below). Which leads to this exchange:
  Sol: So what's the lesson?
  Max: That an answer will come.
  Sol: No, it's the wife! You have to relax!
• 21st Century Serial Killer: When Aaron sees the ring on Charles' finger, he remembers that the Serial Killer he's been looking for had one just like that on his own finger. It leads him to realize Charles is the killer.
• In Ace Ventura: Pet Detective, Ace gets his Eureka Moment when his dog lies across the forehead of a picture of Miami Dolphins kicker Ray Finkle, who he suspects is connected to police lieutenant Lois Einhorn... and the way the dog's hair falls gives him his epiphany... and his entire week's food consumption...
• In Aladdin (2019), when Aladdin starts taunting Jafar about how he'll always be weaker than the Genie, the Genie is initially confused and horrified, but then his expression displays visible comprehension and an "I got you" wink when he realizes that Aladdin is goading Jafar into turning himself into a genie, with all of the rules and restrictions that implies.
• Back to the Future:
  • In the first film, the 1955 Doc has a panic attack after he sees his 1985 self explaining that the time machine requires 1.21 gigawatts of electricity produced by plutonium. Doc says that since plutonium is out of the question, the only natural source of power that can generate 1.21 gigawatts is a bolt of lightning. That's when Marty remembers he has the flyer given to him by the woman campaigning to save the clock tower and realizes that the bolt of lightning that stopped the clocktower can be harnessed to give the time machine enough power to send it back to 1985.
  • In Part II, when Marty realizes he got Biff's dirty magazine in Strickland's office (and that Biff still has the Almanac), Marty laments to Doc over the walkie talkie that he has no idea what to do now or how he's going to find Biff... only to hear the sound of a certain struggle going on in the parking lot.
  Marty: OF COURSE! (to Doc) I gotta go, I got one chance, my old man is about to deck Biff!
• Batman (1989):
  • Vicki Vale is already beginning to suspect something about Bruce Wayne, but the penny finally drops about who he really is when she discovers his parents were murdered.
  Knox: What do you suppose something like that does to a kid?
  • Bruce himself seems to have one when confronting Joker in Vicki's apartment. After Joker asks the question, “You ever dance with the Devil in the pale moonlight?”; it snaps Bruce out of his Let's Get Dangerous! moment. A flashback later on reveals what Bruce realized: that Joker/Jack is the one who killed Thomas and Martha Wayne; he asked the same question to young Bruce.
• A Beautiful Mind:
  • Nash develops his theory out of his friends' fighting over a girl.
  • There's a more serious case later in the movie: Nash realizes he hallucinates when he realizes in all the years he's seen them, the little girl never ages.
• In Beaches, there's Bette Midler's satirical song about the — apocryphal — inventor "Otto Titsling", who supposedly invented the brassiere.
• The Big Short has the scene where Mark Baum talks to Wing Chau, and puts on a massive Oh, Crap! face as Baum realizes the market for insuring mortgage bonds is significantly larger than the market for the mortgage loans themselves, and thus the whole world economy would suffer when that bubble burst.
• In Blazing Saddles, Hedley Lamarr's evil plans all come as a result of these.
• In Blood Work, the detective realizes the meaning of the Code Killer's message ("903 472 568") while looking at a check he wrote for his neighbor, after someone else pointed out that the message doesn't contain a 1.
• In The Cannonball Run, J.J. and Victor debate what to drive in the race while driving around in a boat. They get into an accident and are taken to the hospital in an ambulance. J.J. asks the doctor how long it's going to take them to get to the hospital. The doctor explains that the ambulance can easily slip through traffic due to being an emergency vehicle. Guess what they end up driving in the race.
• Chip 'n Dale: Rescue Rangers (2022): When Ellie is tied up in Sweet Pete's bootlegging facility, Captain Putty forces her to call Dale and tell him that she's fine. However, Ellie tells him something that is supposed to be a coded message for help: that her favorite episode of Rescue Rangers is "When You Fish Upon a Star". Dale watches said episode and, through his bizarre train of thought, manages to correctly guess what's really going on.
  Dale: Alright, think, Dale! Think! Gadget is stuck in a lantern. Lanterns provide light... by using fire! Fire is really cool... but also really dangerous. Someone is in a dangerous situation! Like that time I dropped a bowling ball on my toe. (gasp) Ellie has ten toes! And she probably likes Thai food! Ellie is tied up and in danger! And Chip is with her! It was Putty working with Sweet Pete the whole time! I cracked it! I'm coming, guys!
• Clegg: When Col. Sullivan facetiously suggests that maybe Wildman hired prostitutes to carry out the assassinations, Harry suddenly realises that this is exactly what Wildman has done. Or rather, one specific prostitute.
• Conjoined: When Jerry asks if they would separate Alina and Alisa before prosecuting the latter, it gives Stanley the idea to perform the surgery himself.
• In Death Walks on High Heels, Inspector Baxter has one about how the crime could have been committed when The Coroner makes a comment about the freezer at the morgue.
• In Diamonds Are Forever, James Bond runs through a quick list of locations of Whyte properties Blofeld might be using to run his satellite operation. He and Willard Whyte both realize where it is when he mentions an oil rig off the coast of Baja California.
  Willard Whyte: Baja? I haven't got anything in Baja!
• Die Hard has this a few times:
  • In Die Hard, John McClane is talking to Al on "getting help from the guy upstairs." It then hits John that Hans was near the roof when they ran into each other, and he starts to wonder what Hans was doing up there.
  • Die Hard 2 has McClane chasing Stuart's team and using a machine gun he took from one of them, but it has no effect. McClane wonders how he could have missed at that range and checks the gun to find it's filled with blanks. McClane realizes this means the terrorists were using blanks in their "firefight" with Grant's Special Forces team. Which means they knew the soldiers were using blanks too... which means Grant and Stuart are working together.
  • In Die Hard with a Vengeance, running into a band of under-aged looters alerts McClane that the villain's apparent plan is likely a distraction.
    Kid: All the cops are into something! It's Christmas! You could steal city hall!
• Dogma has one of these near the end; Jay tells Bethany (while trying to get it on, because the world's about to end) about a boardwalk he once took a girl to on a date. Bethany, after learning that the boardwalk has Skeeball, realizes that "John Doe Jersey," of whom her minister was sermonizing about earlier, is God, trapped in a comatose mortal body. Hey, Jay was a prophet (or is that profit?), after all.
• Evolution has some egregious examples:
  • The revelation that the aliens reproduce quicker with fire is brought about by Orlando Jones' character dropping a lit cigarette into a petri dish, seconds after explaining how he hasn't smoked in years.
  • The alien's weakness to selenium is discovered by Julianne Moore taking off her jacket, revealing her periodic table of elements t-shirt.
    • Note that Evolution was, in fact, a pastiche of these kinds of movies.
• A Face in the Crowd: "Oh, if only they heard the way that psycho really talks." Fortunately someone in the sound room heard him and set up the Engineered Public Confession that doomed "that psycho".
• In A Few Good Men, Tom Cruise briefly halts a brainstorming session with the rest of the defense team to look for his lucky baseball bat, which Demi Moore has innocently placed in the closet. Staring into the closet prompts a Eureka Moment that reveals an important fact about the case — the murder victim's clothes were hanging in his closet; if he had really been due to transfer to another post the next morning — as his CO has claimed — his things would have been packed, and his closet empty. Prompting the line "he really does think better with that bat."
• At the end of The Fugitive U.S. Marshall Gerard is having doubts as to whether Dr. Richard Kimble is guilty of killing his wife and has doubts about Dr. Charles Nichols and one-armed man former cop Sikes. So he has his deputies check the phone records for a connection but nothing comes up. Then a deputy notices that a call was made to Sikes from Kimble's car phone right around the time Nichols was driving to give Kimble his keys back, and around the time that Kimble's wife was killed.
• In Ghostbusters II, after the proton packs have no effect on the slime encasing the art museum, Egon figures out it's powered by all the negative emotion in the city. He starts to talk about needing a massive infusion of positive energy to shatter the shell.
  Egon: We need something that everyone in this town can get behind. [looks down] We need... a symbol!
  Ray: Something that appeals to the best in each and every one of us.
  Egon: Something good.
  Winston: Something decent.
  Peter: Something pure.
  [close up of the Statue of Liberty image on Ecto-1A's license plate]
• An unexpected source: in Godzilla vs. Biollante, a scientist works out the flaw of a recent attempt to neutralize Godzilla via Applied Phlebotinum by seeing dry ice hauled about for emergency refrigeration in the wake of the unthwarted monster attack.
• In Harry Potter and the Chamber of Secrets, Harry and Ron are unable to get through the barrier at King's Cross to get on the Hogwarts Express, and are wondering what to do. At a loss, Harry suggests they just go back and wait by the car, which gives Ron the idea to use his dad's flying car to get to Hogwarts.
• High School Musical: A villainous example from Sharpay, when she gets an idea to make it so that Gabriela can't make it to the auditions.
  Sharpay: Okay, so the decathlon and the basketball game are on Monday, and the auditions are on Friday. Too bad all of these events weren't happening all on the same day... at the same time.
• In Homeward Bound: The Incredible Journey, Chance's "if I don't survive" speech helps Shadow figure out a way to get rid of the cougar chasing them.
  Shadow: Seesaw? Seesaw! Chance, you're a genius!
  Chance: I am not!... What's a genius?
  Shadow: Never mind.
• In Hot Fuzz, Nicholas Angel's suspicions are stumped by the question of how one person could be in multiple places at once. When he and Danny Butterman go visit the convenience shop, the conversation that takes place between Danny and the clerk causes Nicholas to suspect multiple killers. What's more, the shop clerk who triggered the Eureka Moment is one of the killers herself. Oops.
• The Hunt for Red October:
  • During the briefing for Jeffrey Pelt on Soviet captain Marko Ramius, Jack Ryan realizes today's the anniversary of his wife's death, thus Ramius' real goal isn't attacking the United States, but defecting to them, instead. When he figures this out, Ryan quietly mutters "You son of a bitch...", before saying it loud enough for everybody else to hear, leading Pelt to quip "You wish to add something to our discussion, Dr. Ryan?"
  • Later, Ryan tries to mull over how Ramius would manage to get the rest of his crew off the sub as part of his plan to defect.
    Jack: We don't have to figure out how to get the crew off the sub. He's already done that, he would have had to. All we gotta do is figure out what he's gonna do. So how's he gonna get the crew off the sub? They have to want to get off. How do you get a crew to want to get off a submarine? How do you get a crew to want to get off a nuclear sub....
• In Independence Day, a scientist's father tells him to get up off the floor so he doesn't catch a cold, which gives him the idea to disrupt the aliens' force fields by uploading a virus into the mothership's computers in a reference to The War of the Worlds. This scene is parodied in the "Cancelled" episode of South Park. However, this parody is itself not an example of Eureka Moment, but of Bat Deduction.
• In Inside Man, a chance comment a rookie cop makes to Denzel Washington's character allows him to figure out how exactly the hostage takers were able to stay ten steps ahead of the police.
• Happens in Interstellar when Murph finds out her father is actually the "Ghost" that contacted her in her childhood and also when discovering the solution to Brand's equation. She even shouts "Eureka!" out of joy, throwing her papers everywhere after writing the solution on them.
• In the Line of Fire: Clint Eastwood's character figures out the meaning of a word with seven letters after a chance remark by a character played by Joshua Malina.
• I, Robot features several effective examples of this trope including... "...the right man for the job...?" "...follow the bread crumbs..." "...I think my father wanted me to kill you..." etc, etc.
• In K-9 Dooley is growing frustrated with a case he's working. His girlfriend Tracy told him that he needed to relax, and the answer would come to him. Not much later, things are getting romantic between the two, when lo and behold, Dooley has an epiphany and must rush out the door with his four-legged sidekick.
• In Kid Detective (2020), Abe is well and truly stumped on the entire mystery until a childhood friend explains that he was wrong about one his very first cases. This makes Abe realize that case was a setup and the culprit behind it is the one he should be investigating.
• L: change the WorLd has one character hiding clues in math problems. L figures out the solution when accidentally given a clue.
• In the first Legally Blonde movie, when Elle is defending her client, a fitness guru accused of killing her husband to get ahold of his business assets, she's a nervous wreck while asking the stepdaughter what she was doing that day. Elle gets her second wind when the witness states that she took a shower after her bi-yearly permanent hair treatment, and Elle surprises the entire court by mentioning that taking a shower after a permanent will render the chemicals' effect on the hair ineffective. After some more questioning its revealed that the stepdaughter was waiting to ambush his father's wife, but accidentally shot him dead, and pinned it on her stepmother.
• In The Mad Magician, Alice Prentiss experiences her Eureka Moment when her husband is reading her details of an unrelated murder in Fall River, and says that a neighbour saw the killer but he was masked. This makes he realize that the man she thought was Ormond could have been Gallico wearing a Latex Perfection mask.
• Major League: The Indians' manager is about to send hopelessly wild pitcher Ricky Vaughn to the minor leagues. During their conversation, the manager off-handedly mentions another pitcher who went down to the minors and had a successful career and points at his photograph. Vaughn squints in the pitcher's direction, and the manager suddenly realizes all his problems are related to poor vision.
• Crossed with Oh, Crap!; In Man of Steel, Lois tells Clark that they gave her a Mind Probe and learned all her secrets. Clark replies that Zod was inside his head as well... then he connects the dots and realizes they know where he lives, probably enforced by him cocking his head slightly like he was listening.
• In The Man Who Knew Too Much, Ben McKenna follows the lead of spy Louis Bernard's dying words, "Ambrose Chappell", to search for the kidnappers of Ben's son. Ben visits a taxidermy shop owned by a man named Ambrose Chappell, only to learn that Mr. Chappell has no association with the criminals. As Ben's wife, Jo, waits anxiously for him to return to their hotel room, one of her friends, Val, asks her the name of the person Ben's searching for. Val mistakenly calls him "Church", so after Jo corrects him with the word, "Chappell", she pauses, then exclaims, "It's not a man, it's a place! It's Ambrose Chapel!" Jo's friends proceed to help her find the address of this chapel in the phone directory, before she leaves them to search there.
• Marvel Cinematic Universe:
  • Iron Man 2: While trying to perfect the arc reactor, Tony suddenly finds inspiration in his father's miniature model of the first Stark Expo. Of course, his dad did that quite on purpose during the video he left behind for Tony.
    Howard Stark: This is the key to the future, Tony.
    [camera cut to the City of the Future]
    [camera cut to the Unisphere]
    [camera cut to a prototype arc reactor]
  • It seems that they did some research on the missing element. The element in question (118) does exist as "Ununoctium" though it is radioactive and only lasts for a very short time before decaying. It can only be synthesized with the help of a particle accelerator.
  • Happens to Tony again in The Avengers, when he realizes that Loki is using Stark Tower to launch the alien invasion.
    Tony Stark: He knows he has to take us out to win, right? That's what he wants. He wants to beat us, he wants to be seen doing it. He wants an audience.
    Steve Rogers: Right. I caught his act in Stuttgart.
    Tony Stark: Yeah. That's just previews, this is... this is opening night. And Loki, he's a full-tilt diva. He wants flowers, he wants parades, he wants a monument built to the skies with his name plastered... Son of a bitch.
  • Spider-Man: Homecoming: Used by Adrian Toomes as he drives his daughter and Peter to the homecoming dance. His first clue was when Peter tried to bluff that he was at a party his daughter was at, the same night he and Spider-Man met, but she interrupts and says that he was barely there. Then he follows it by talking about the elevator incident in DC, with Peter himself confirming he wasn't up there, but remarking it was lucky that Spider-Man saved them.
    Toomes: [as the light ahead of him turns green] Good old Spider-Man.
  • Nonverbal one in Avengers: Endgame. As Thanos regains control of the Gauntlet and about to dust the universe again, Tony looks at Dr. Strange as if asking "what are we going to do now?". Strange wordlessly raises his finger, trembling all the time, and at that moment Tony understands that he will have to make the ultimate sacrifice to turn the battle around, the only one out of millions of outcomes where they actually win.
• Master and Commander: "Let me guess. A stick?"
  Midshipman Blakeny: It's a rare phasmid, sir... It's an insect that disguises itself as a stick in order to confuse its predators.
  [later]
  Captain Jack: A nautical phasmid, Doctor... I intend to take a greater interest in the bounty of nature from now on. I had no idea that a study of nature could advance the art of naval warfare! Now to pull this predator in close and spring our trap.
• Mega Shark vs. Giant Octopus: After having sex the two scientists realize pheromones are the key. To capturing the monsters, that is.
• Men in Black:
  • Men in Black:
    • The title characters have been racking their brains trying to figure out where the "Galaxy" is. Their only hint is that they were told it's "on Orion's Belt" by a dying alien^note this confuses the Agents because they think the alien is referencing the constellation Orion, but that "belt" has no galaxies on it. When Agent J sees Frank barking at a cat on the street, he realizes the alien meant collar: the alien had owned a cat named Orion, and the "Galaxy" is a trinket the size of a marble attached to its collar. (This is foreshadowed when the prince is eating with his countryman right before Edgar attacks, and uses words that aren't quite the right English terms.)
    • And it happens again later on, when the MIB are trying to figure out where the Bug might get a ship, and Jay spots the mural of the 1964 World's Fair, where they'd stashed a pair of flying saucers decades before and passed it off as an avant garde art installation.
  • Double Subversion in Men in Black II, where Agent J starts to decode a ridiculously complicated chain of arrows in a pizza shop which leads him nowhere, because he missed a much more obvious clue at the first arrow. However, the free-association links he found do turn out to be quite close to the actual plot.
  • Discussed in Men in Black 3. In 1969, Jay and the young Kay are trying to find Boris, Kay suggests heading to the nearby diner and getting some pie, saying "My granddaddy always said: 'If you got a problem you can't solve, it helps to get out of your head.' Pie. It's good." While at the diner, they see some disgruntled New York Mets fans.
    Jay: (sotto, to Kay) That's funny. The Mets actually win it all this year.
    Young Kay: Oh, yeah.
    Jay: No, I'm serious.
    Young Kay: I'm sure.
    Jay: Look, three months from now, your buddies down there are gonna be calling them "the Amazing Mets" and "the Miracle Mets"...
    (beat)
    Young Kay: What? What you got there, hoss?
    Jay: The Archanan said, "It's amazing! It's a miracle! I'll see you at the game." I know where he is.
    Young Kay: (smiling) Told you to trust the pie.
• In Mortal Engines, when Hester sees the shrine to Medusa in Shan Guo, realises the central eye is the same as the locket her mother gave her, and opens it to discover the crash drive for the MEDUSA system.
• In Murder!, Sir John realizes when he takes a sip of his brandy cocktail that if Diana had been lying about having drunk the brandy, she wouldn't have been so equivocal in her denial of the murder.
• William has one in The Name of the Rose book considering the secret of the library. Adso remembers how Salvatore said "tertius equi", which is Canis Latinicus for "The third of horse" (when he meant "the third horse"). William concludes: "the first and the seventh of the four" really means "the first and the seventh of the word four", and "four" is "quattuor" in Latin, so you have to push the letters Q and O!
  • They had a minor one earlier, when Adson dreamed a story similar to the "Coena Cypriani", a kind of The Bible parody. Which helps William to remember that there was a book in the library consisting of four texts, one of them a comment for the Coena Cypriani, another one the book they're looking for.
• National Treasure:
  • The entire plot hinged on the protagonist's ability to solve puzzles and uncover secrets in this manner. Granted, the hint was invariably directly related to the solution ("Pass and Stow" was written on an ad for the Liberty Bell, the correct time was drawn on a famous picture of the building it was stored in, etc), far more so than typically for this trope.
  • The Big Bad also had a few of these, such as his realization that the reason why the word "Silence" is capitalized in a coded message is because it's a name (Ben Franklin's pen name) or when they arrive to the Liberty Bell exhibit only to realize that he's supposed to look where the bell was originally located not where it was moved 100 years later.
• In Oz the Great and Powerful, Oscar is starting to feel overwhelmed by the knowledge that he has to fight two witches armed with very real magic that he doesn't have, and the only thing behind him is an army of craftsmen. While tucking in the China Girl at bed time, he tells her about Thomas Edison, and that he could use his knowledge of natural science to create wonders and realizes that he can use his own knowledge of special effects and theatrics to basically bluff the witches into submission.
• In Philomena, Martin realizes that Michael was aware of — and took pride in — his Irish ancestry.
• Towards the end of Planes, Trains and Automobiles, as Neal Page is finally heading home to his family in Chicago, he starts thinking about having Thanksgiving dinner with them. This segues into thinking about his time with Del Griffith, specifically one cryptic comment Del made: "I haven't been home in years...". Neal suddenly realizes the truth about Del, and he returns to the train station to confront Del, who confesses he's been a homeless drifter since his wife Marie died 8 years earlier.
• In Real Genius, Knight's frustration at his sabotaged laser failing leads him to a freezer, where he realizes "It must be frozen..." and invents an entirely new and better laser using a frozen core.
• Based on the Romance of the Three Kingdoms saga, the Chinese movie Red Cliff has Boisterous Bruiser Zhang Fei, not known for his tactical genius, but still unwittingly blurting out vital insights more than once. Towards the end of the movie, his comment on the enemy battle fleet ("those ships could give us more firewood than we'll use in our lifetime") leads to Zhou Yu's plan to set the entire fleet on fire.
• In Seven (1979), Cowboy is trying to work out how to deal with Kimo's bulletproof limo when he spots a couple of kids pitching horseshoes in the park. A light bulb goes off and exclaims "That's it! Horseshoes!", much to Jenny's confusion.
• Sky Captain and the World of Tomorrow. The title character is given a staff and told to "Follow Rana. The staff will lead you to Totenkopf".
  Polly: Have you looked at this? There's markings on it, like a ruler. And there's a moon and a star.
  Joe: "And all I ask is a tall ship, and a star to steer her by." A star. He wasn't talking about a place, he was talking about a star! Rana is a star! Ancient sailors used to navigate by using the night sky. They could determine their position by the moon and the stars. The Vikings were known to create maps for certain stars, latitude tables that required a key to decipher them. The key was called Jacob's staff. This has to be the key!
• The Sniper: Lt. Kafka experiences a minor one (in that it does not immediately bust the case) while complaining to Sgt. Ferris about the tips coming from the public, including one from the woman in the dunk tank talking about Miller hurling baseballs at her.
  Lt. Kafka: "A letter from a man who says..." <Beat> "Baseballs?" (gets a thoughtful look on his face and gets up and hurries from the room)
• The Snowball Express: John gets his idea about turning the mountain into a ski resort when Wally talks about riding all over it in his snowmobile.
• In Some Guy Who Kills People, the sheriff is struggling to find a connection between the victims aside from them all coming from the same town. His Clueless Deputy, who has a habit of making inappropriate jokes, remarks that if there were six more of them, they'd have a baseball team. That gives the sheriff his lightbulb moment as he grabs the yearbooks and discovers the victims had all been on the high school basketball team.
• In Spies Like Us, Austin Millbarge muses over accidentally launching an ICBM and apparently starting World War III, saying "And to think my guidance counselor said I'd never amount to anything...". After which, he suddenly says "GUIDANCE!? SOURCE PROGRAMMABLE GUIDANCE!" and thinks up a plan that saves the day.
• In The Film of the Book The Spy Who Came in from the Cold, the burnt-out British spy Leamas is seconds away from successfully competing an assignment to destroy an enemy agent when stupid mistakes by his service in London destroy the entire plot, allowing the enemy agent to escape. You look into his face and you realize that the entire plan was about saving that agent who has come over to the British and killing the man who suspects him. Leamas was just a pawn.
• After two weeks of poring over a cartouche in the original Stargate movie, Daniel Jackson finally figures out that the symbols aren't hieroglyphs, but star constellations when he sees a picture of Orion on a guard's newspaper and recognizes the shape as one of the symbols.
• In Stranger Than Fiction, the author figured out how to kill off the main character after seeing someone drop an apple. She mentions she'd never be able to explain the connection. It makes sense when you see it.
• In the 1974 film The Taking of Pelham One Two Three, the police car carrying the ransom money crashes on the way to the hijacked subway train. With no time left to spare before the hijackers kill a hostage, Garber manages to do some quick thinking when he realizes that the hijackers, who are underground and only in contact with the outside world through his dispatch terminal, don't know that the car has crashed.
  Police officer: If they know the truck is wrecked, how can they expect us to be on time?
  Garber: They don't know anything down there. How can they know anything when they... that's it.
  <switches on the radio with Mr. Grey>
  Garber: Pelham One-Two-Three, the money has arrived. I repeat, the money has arrived!
• In Tell No One, Alexandre has received a mysterious e-mail from someone claiming to be his dead wife, Margot, who's left him a username and password to answer another e-mail that's being sent later. Alexandre can't access the account no matter how he tries, much to his frustration. That night, he's out walking the dog when he hears "With or Without You" playing, and realizes what the username and password are really *supposed* to be, allowing him to go to an Internet cafe and access the account.
• In Thank You for Smoking, Nick hits upon his strategy for the congressional hearing while watching Bobby eat apple pie covered with cheese.
• Tremors. The main characters are desperately trying to figure out a way to escape from the Graboids, which perform a Dig Attack. Valentine says "We need a helicopter. Or a goddamn tank!" Earl realizes that they can use a bulldozer to pull an open semi-trailer and carry everyone to safety.
• At the end of The Usual Suspects detective Kujan lets Verbal Kint go after interrogating him about the ship massacre, convinced by Kint's story (told in flashbacks that make up most of the movie) that Dean Keaton is legendary criminal Keyser Soze. After Kint leaves, Kujan comments on the sloppiness of his partner's desk, and his partner says the mess makes sense if you take a step back and look at the whole thing. Kujan chuckles, drinks his coffee, looks at his evidence board and realizes Kint made up the whole story based on things tacked on the board, complete with Kujan dropping his coffee mug and it shattering in slow motion.
• WarGames
  • While trying to figure out the password to log onto the WOPR computer, David and Jennifer watch a short film featuring Falken and his son. David asks about the son's name, and when she answers that it's "Joshua", he mutters "It can't be that easy..." It does indeed turn out to be the password.
  • During the tense final scene, when Falken tries to access Joshua with his password and finds it's been taken out, David asks what they're going to do. Falken says "I don't know. Do you?", then for some reason, Jennifer says "I told you not to play games with that thing". So, David thinks for a moment, then says "It's games. GAMES!", and proceeds to play games with Joshua.
• In We're the Millers David conceives his "let's pretend to be a family" plan after seeing a police officer helping out a family in a RV.
• Who Framed Roger Rabbit:
  • As Eddie Valiant leaves a movie theater, a newsreel tells the news of how Maroon Cartoons was sold to Cloverleaf Industries, the same company that bought the Red Car trolley line and bid for ownership of Toontown. He runs back in and shouts, "That's it! That's the connection!"
  • He has another one following Doom's comment to the weasels about "laughing yourselves to death". You can literally hear the light bulb go on in his head.
• Yves Saint Laurent: Yves thumbs through an art book and sees a Mondrian painting...the rest is history.

Literature

• Miranda has one at the end of When You Reach Me.
  I am jumping up and down because at the very moment Dick Clark said the word "Go," it was like an invisible hand reached out and snatched away my veil. And for almost a minute, I understood everything. When that veil isn't hanging down right in front of a person's face, a minute is long enough to realize a lot of things.
• Agatha Christie loved doing this in the Hercule Poirot novels. Very frequently, he fits the pieces together after inspiration from a chance remark by one of the other characters; to Poirot's credit, he never fails to explain precisely how it helped him break the case.
• In The Pale Horse by Agatha Christie two people have Eureka moments in short succession. Several people have died, supposedly by magic. Mystery writer Ariadne Oliver suddenly realizes that all the deaths have one thing in common: all the victims were losing their hair when they died. She knows this is a vital clue but she has no medical training, so she doesn't know what it means. She calls Mark Easterbrook, a doctor who has been investigating the deaths, to tell him what she has realized, and he has his own Eureka moment, realizing that all the deaths were due to Thallium poisoning.
• The Cat Who... Series: Every book features Koko the Siamese doing something odd which eventually leads to Qwilleran having a Eureka Moment. How plausible Koko's behavior is, either taken at face value or with the strong hint he's trying to give clues, varies considerably.
• In book two of the H.I.V.E. Series, Laura has one of these in the form of Dreaming the Truth.
• Lampshaded in The Burglar Who Traded Ted Williams: While Bernie Rhodenbarr is talking with a friend, she mentions the Cat Who... series, when his cat suddenly launches into strange behavior and Bernie solves the crime. Subverted, in that he'd already solved the crime, but didn't care about revealing the result. When the cat acted, as if on cue, he decided to play along.
• A Song of Ice and Fire:
  • Sansa supplies her father with one when she says that Joffrey (who she has a mad crush on, the poor girl) is nothing like his father, Robert. This finally makes Eddard realize that none of Cersei's children take after Robert — though all of Robert's bastards do — and the kids are most likely the product of incest between Cersei and her brother, Jaime.
  • Tyrion gets one two books later, when the readers have all pretty much forgotten about the never-quite-solved mystery of who sent the assassin with the dagger to try to kill Bran from the first book, when he hears Joffrey bragging about how he's very familiar with expensive things like Valyrian steel. Because the chapter is told from Sansa's point of view, the readers only find out what's on his mind when he gets her alone for long enough to ask "Hey, do you know if Joffrey had any reason not to like your brother?
• In American Gods, this is how Shadow figures out where a small-town serial killer has been hiding his victims' bodies, acting on a comment from a god who knew what was going on, and was trying to clue him onto it.
• In "The Honour of Israel Gow," Father Brown has an explanation that he thinks covers almost all of the strange evidence they've found — snuff without snuff boxes, candles without candlesticks, holy images with the halo around the baby Jesus removed — but not the fact that the title character decapitated a dead man and stole the head. It's not until his friend Flambeau mentions going to the dentist that Father Brown manages to tie that in with the rest of the evidence. He realizes that the dead man must have had a gold tooth. All of the missing things are those that are made of gold. Israel Gow was promised "all the gold in the castle," and taking it literally, Gow took everything that was gold (the snuff boxes, the candlesticks, etc.) while leaving behind everything that wasn't.
• Isaac Asimov:
  • Dr Asimov wrote an essay about how this sort of thought process works called "the Eureka effect". It's even made it into a few high school literature books.
  • Elijah Baley constantly tries to "solve" his cases by fixating on a new piece of evidence, until something happens that makes him revise his understanding of the evidence he already has.
    • The Caves of Steel: In the first novel, Lije Baley figures out the murder mystery when his partner casually brings up Enderby's glasses. All pieces of the puzzle then come together: Lije realizes that Enderby (who was earlier established to be psychologically incapable of killing a human) accidentally murdered a person, instead of destroying their robotic lookalike, because he couldn't see clearly when his glasses shattered. Then Daneel has a different one when he begins to grasp the distinction between 'legal' and 'ethical', which humanizes him in Baley's eyes.
    • The Naked Sun: In the second novel, Baley asks Daneel to "give him a hand". The robot responds by looking at his hand as if he was supposed to actually give it to him, leading Elijah to realize that the murder weapon was a robot's detachable arm.
    • The Robots of Dawn: The third and final book in the series even barely gets away with justifying it. Baley has a eureka moment three times just before falling asleep. Each time he forgets what it was he discovered by the time he is fully awake again. Fastolfe at one point suggests using a potentially dangerous mind probe device to try to help Baley remember what it was he realized, but Baley does not take him up on the offer. Giskard eventually admits that he used his telepathic powers to prevent Baley from remembering what he had discovered each time in order to protect the secret of Giskard's telepathic abilities.
  • Foundation Series' "The Mule": Bayta has been thinking about the fact that she felt desperate both during the Time Vault event and in Neotrantor. When recently converted Han Pritcher reveals to them that the Mule was the one that caused the desperation in the Time Vault, she makes the connection that Magnifico, the half-idiot jester she has been friends with, is actually the Mule.
  • "The Last Trump": Etheriel realizes that the Act of Ascendancy is scheduled to take place in 1957, but it doesn't specify Anno Domini; arguing with God that the Act should be postponed until everyone on Earth agrees that the current year is 1957.
  • Powell and Donovan:
    • "Reason": Powell's moment of realization comes while inspecting the report from Cutie's shift during the electron storm. The robot was able to maintain focus far more precisely than any human could, which means his Robot Religion is useful for training each of the successive QT models on how to operate the remote space stations.
    • "Runaround": Powell and Donovan are quite proud of themselves for thinking of using the mining laboratory to create oxalic acid to chase Speedy away from the danger. Up until they realize, too late, that it only shifts the problem a few meters in one direction or another without solving the Logic Bomb.
    • "Catch That Rabbit": Powell's moment of clarity occurs just in time for them to shoot one of the subsidiary robots, getting Dave to work again. Using the analogy of subsidiary=finger, Powell realized that the dancing and marching was due to Dave "twiddling his fingers" while he worked out what needed to be done.
• Isaac Asimov and Janet Asimov's Norby's Other Secret: In chapter six, while Norby and Fargo are racking their brains to figure out how to open the hassock, Jeff suggests they take a break by singing a few songs. Fargo calls him a genius and starts laughing, leaving Norby to explain that Fargo now thinks the numbers they'd deciphered stand for musical notes.

• Timothy Zahn likes this trope. Or, more accurately, this trope fits his style. Many of Zahn's original works are First-Person Smartass, and the settings are similar to Hitchcock-style suspense/intrigue mysteries, so there's guaranteed to be one when the protagonist finally puts the pieces together. (Though the reader, unless he figures it out too—which is sometimes possible and sometimes not—won't know until The Summation.) Some examples:
  • The Icarus Hunt has at least two: One when a comment makes the protagonist realize another person's murder was connected with something completely different than he'd been assuming; another when a different comment triggers a flashback. The Summation indicates he may have had another couple more along the way that the audience wasn't even privy to.
  • The Quadrail Series tends to have one per book, minimum; most notably, the moment in Night Train to Rigel when Compton figures out how the FTL trains work.
  • This even shows up in his Star Wars Expanded Universe work, though those get more promptly revealed to the reader: in Survivor's Quest, a random comment by Luke triggers a flashback for Mara, in which she recognizes a major inconsistency in some of their companions' back story.
  • And finally, one for Leia in The Last Command. Talon Karrde mentions how he was a Chimaera prisoner, and for Leia, "suddenly, all the pieces had fallen into place...and the picture they formed was one of potential disaster."
• Aside from the few times they recognize the answer instantly, the characters in The Da Vinci Code seem to rely solely on this trope to solve all the various puzzles and sub-puzzles. For the last puzzle before the book's climax, we don't actually get to see the main character work out the answer.
  • We don't get to see it, but we do get the lead in. The answer to the last puzzle is a word: apple, and the last thing Langdon happens to look at before his off-screen Eureka Moment is an apple tree.
• Nero Wolfe does this quite a bit. He's got all the pieces, but can't make them fit together, Archie (or one of the suspects) says something that causes him to look at one particular thing in a different way, and everything falls into place. He will often admit to Archie when it was something that he said or did; if it was someone else, he saves the information for the Parlor Scene. Both Archie and the reader know one has just occurred when Nero starts doing his "lip exercises".
• Subverted, while lampshading the subversion, in Mil Millington's "Love And Other Near-Death Experiences", in which the central character has a startling realization that he recognizes would qualify as a Eureka Moment — except that nobody did or said anything to trigger it, it just happened without prompting.
• Harry Potter:
  • In Half-Blood Prince, a sarcastic comment by Harry ("Fifty-seventh time lucky?") about his inability to get a crucial memory of Voldemort from Slughorn inspires Ron to suggest Harry use his luck potion, which proves effective. A similar scene occurs in the movie, only (in keeping with the screenwriter's general inclinations) reversed: Ron's comment inspires Harry.
  • In Deathly Hallows, we're treated to Harry's entire train of thought as a broken talking stone gargoyle triggers his memories and he realizes exactly where the last Horcrux is hidden.
• In Memory, Sorrow, and Thorn, near the climax of the third novel, Binabik the troll has a classic Eureka Moment during his party's escape from the Norns beneath Asu'a, as a result of an offhand comment from the dwarrows who are aiding them. Unconventionally, this leads not to the solution to the plot but the horrifying realization that the heroes have been doing the Big Bad's bidding the entire time.
• In the grand tradition of mystery novels, happens frequently in Ngaio Marsh's Inspector Alleyn series. An interesting departure is that the Eureka moment for Alleyn usually occurs near the middle of the book, with the reader catching up as more evidence is gathered.
• Discworld:
  • Feet of Clay:
    • Subverted where Vimes specifically warns against this.
    • Played straight at the end, when remarks of Detritus and Fred Colon make Vimes realize the Big Bad had been rubbing the hints of his plot in Vimes' face, assuming Vimes wouldn't get them.
    • Lampshaded in that "eureka" is a Ephebian word meaning "Bring me a towel". And in fact, we learn this is a regular occurrence for Ephebian philosophers, to the point that nearby stores keep a large supply of soap, towels and bath salts.
  • Subverted in Reaper Man; Inventor Ned Simnel is trying to think up a way for his combination harvester to move without a horse when a blast of steam goes off. Ned just gets annoyed on how he's always getting interrupted when trying to think. According to The Discworld Companion, this has happened over a 150 times.
  • Subverted in Moving Pictures. CMOT Dibbler has been selling advertising space in some pictures, but is told to stop. Then he hears about a mistake someone made while editing a film, leaving in a frame which was just a picture of gold. Nobody noticed, but everyone was thinking about gold when they left the theater. It looks like he's about to figure out a way to sell advertising after all... but he puts in five minutes of film depicting what he's trying to advertise, on the reasoning that if one frame can do that, five minutes worth must work wonders.
• In Dorothy L. Sayers' Whose Body?, Lord Peter Wimsey's moment of revelation is explicitly compared to staring at jumbled letters until they formed a word of their own inclination.
• In Remote Man, Ned comes up with his plan to bring down Laana's smuggling operation when he's browsing in a dime store. He picks up a pin cushion that he discovers has a music box inside playing a familiar tune: The Entertainer. This brings back memories of watching The Sting with his father, which in turn sparks his plan, which is to invent a person, a rich businessman with his own fabricated website, to be a client of Laana.
  • Earlier, Ned overhears a conversation mentioning "an anchorman in Kingston". When he later learns that Kingston is the capital of Jamaica, he realises that what he heard was "a nanka-man", nanka being a local term for the Jamaican Boa.
• "Take a chill pill" in Mystery Team.
• When Chichikov gets the idea for his scam in Dead Souls.
• In Heroes Die, Toa-Sytell has one when he reads the Monastic records on Caine and realises that he's an Aktir.
• In Anno Dracula, Genevieve and Charles are struggling with their investigation into Jack the Ripper's murders. Genevieve wishes aloud that Dr. Seward were with them, as he treated all the victims and could have told them what they had in common. As soon as she says this, Charles realises something; They had Seward in common. Jack Seward.
• Happens quite a bit in The Dresden Files. Most recently, in Cold Days, Harry was talking with someone about his daughter and how much he would give to not have her hurt from any source, which makes him pause. Seconds later, he unravels a plot that's been in play for eight books.
• In I Want My Hat Back, the Bear, after a long and fruitless search for his hat is asked to describe it: "It's red and pointy and... I HAVE SEEN MY HAT!"
• In Astrid Lindgren's Emil of Lönneberga books, there is a part where a man buys an unshod horse. All attempts to shoe it fail due to the horse kicking, and one man remarks that the buyer was cheated — at home, they tried to shoe it twenty times. Angry, the trader says anyone can have the horse for free, but when Emil takes him up on the offer, says he'll need to get him shod first. However, the horse's reaction reminded Emil (a five years old) of his family's servant, and he realized that the horse was merely ''ticklish''. So, he manages by holding the horse's hoofs, which have no nerves by definition. The trader tries to back out of the deal, but the crowd forces him to keep his word.
• In the thriller The Day Before Midnight, a group of commandos take over a missile base in Maryland but are delayed as the launch key is sealed behind a stone block that will take nearly a day to burn through. The military assumes they're dealing with some radical militia group, but Peter, the base's designer, isn't sure. It's then discovered the "terrorists" are actually a batch of renegade Spetsnaz commandos as Peter realizes they have "figured out how to win World War III." As he explains, if they launch, the Soviet Union may lose about 30,000 people, but the Soviet attack will take out most of the U.S. When the leader of the American forces points out the obvious problem in that the American counterattack will wipe out Russia, Peter says it won't. He reminds them that when the commandos took the base, they sent out a short-burst radio message Peter now realizes was a signal to a compatriot to hold off on the action that guarantees the U.S. response is hopelessly crippled to the point they may not get anything in the air at all.
  Peter: You better kick this over to the FBI because if I'm right, he's gonna launch here and then he's going to nuke D.C.
• Ellery Queen is prone to these. For example, in The Scarlet Letters he is watching some wet paint run in the rain when the meaning the victim's Dying Clue suddenly becomes apparent to him.
• In the Vorkosigan Saga, Lord Miles Vorkosigan is prone to this; for instance in Diplomatic Immunity,
  “The crime isn't murder,” Miles whispered, his eyes widening. “The crime is kidnapping.”
  The murders had come subsequently, in an increasingly panicked cascade, ...
  “My lord, are you all right—?”
  Ekaterin's voice, in a fierce whisper: “No, don't interrupt him. He's thinking. He just makes those funny leaking noises when he's thinking.”
• T*A*C*K: Often, just before "turn the page for the solution". Another character will usually make a reference to something vaguely related that will trigger a "I just figured out the answer!". It's usually Toria who triggers Will, but occasionally other characters will trigger Will or Toria into figuring things out.
• Wet Desert: Tracking Down a Terrorist on the Colorado River: Grant realizes that the bomber is aiming at restoring the Colorado River delta, after figuring that the bomber's warning of a poisoning of the All-American Canal does not fit that of a terrorist trying to kill people.
• In The Dry by Jane Harper, this is how Aaron Falk cracks the case of whether a Pater Familicide was real or a murder staged by someone else. In a casual conversation about a customer with gambling problems, The Bartender mentions that while gamblers always look for loopholes and strategies, it all comes down to backing the right horse. Back in his hotel room, Aaron realizes that all his theories so far have been built on one fatal assumption - that whoever killed the family would have a grudge against the father, his old friend. It never occurred to him that his friend's *wife* might have been the real target.
• A big theme of "Legwork" by Eric Frank Russell is that the dull, dreary legwork gives us more opportunities for Eureka moments. Without all the investigation of the bizarre bank thefts, the police commissioner would not have been able to connect them with Harasha Vanash's UFO.
• Aaren has one in the second Sky Jumpers book, Forbidden Flats, after Alondra mentions the periodic table of elements. It leads him and the others to deduce that iron's magnetic properties may have been transferred to ruthenium.
• The title character of Franny K. Stein does this in several of the books.
  • Attack of the 50-Ft. Cupid has Franny trying to figure out how she can stop the titular gigantic cherub. Remembering her little brother Freddy snarking about using a reverse setting on the Biggerizer so she could shrink her mouth, Franny gets the idea to use the invention to enlarge herself so that she and the giant Cupid would be on equal footing.
  • In The Invisible Fran, Franny gets the idea to become invisible and whisper suggestions into her friends' heads to lure them into pursuing mad science like she does after seeing her chameleon use its camouflage ability to sneak up on her dog Igor.
  • In The Fran That Time Forgot, Franny glances at her Time Warp Dessert Plate she invented for the science fair when everyone at school laughs at her Embarrassing Middle Name, which inspires her to retool her invention and use it to go back in time to change her middle name.
  • In The Frandidate, Franny tries to think of a way she can make everyone want to vote for her for class president. She gets her idea after noticing Igor's uncanny ability to get her what the wants before she even asks, her chameleon being able to change itself when she accidentally sits on it and her parrot imitating her squeal when she sat on the aforementioned chameleon. This makes Franny realize that she can win over the student body by creating a suit that changes her appearance to match everyone's interests and enables her to say exactly what they want to hear.
• A Nice Derangement of Epitaphs by Ellis Peters has an interesting example, where Simon Towne has an epiphany regarding one of the mysterious deaths after George Felse repeats a comment made by his son Dominic. The interesting part is that Simon was present when Dominic made the comment in the first place, but it didn't trigger an epiphany then because he didn't have enough of the other pieces of the puzzle yet.
• Warrior Cats:
  • In Tigerclaw's Fury, Tigerclaw's reflecting on his situation while looking for moss to cover his wound, but instead finds leaf mulch. This makes him realize that his goal to become leader can be attained in more than one way too: while he might not become ThunderClan's leader, there are other options.
  • In Shattered Sky, StarClan has given the cryptic advice that in order to defeat the villain, "the Clans must remember their names". Everyone's a bit baffled at what this means, but then Alderheart happens to walk past Hawkwing telling his daughters about SkyClan's history and how they certainly live up to their name due to their attack-from-above techniques. Alderheart realizes that this means that each Clan must use their own unique battle strategies to fight Darktail.
• In "Ayla and the Birthday Brawl" in the Whateley Universe, Phase has a Eureka Moment in the middle of the final battle of the story. It nearly turns into a Brick Joke when we don't get to hear the deduction until well into the next novel, as the attack used by the Necromancer tells Phase that there is a link between the Necromancer and Hekate, another of their Big Bads.
• Seven Stars: In the chapter "The Trouble With Barrymore", the first-person detective protagonist has one when Geneviève mentions that they don't even know if the key part of the prophecy (which is in French) is supposed to be translated into English, or if it's a French translation of something in a third language. The key phrase is "Maison Blanche", which in English is "White House"... and in Spanish is Casa Blanca.
  This was what it was like. When you saw it, and nobody else did. This was what made a detective.
• The Lotterys More or Less: While Sumac is watching The Sound of Music at the Warming Center, at the point where the song about Liesl and Rolf being in love is playing, it immediately occurs to her that Catalpa, her sister, is crushing on Luiz.
• Katt Loves Dogg: Oscar has one regarding his cousin Romanldo's love poem to Molly's cousin Violet. The reason the lines are spaced the way they are is so that the first letter of each line can spell out the secret message "Meet Me At The Giant Stones".
• Space Case: While watching the security footage of Dr. Holtz before he goes out the airlock, Dash and Kira take note of Dr. Holtz's hand movements in the video. Dash thinks of them as signs, and it leads him to realize Dr. Holtz is relaying a message in sign language.
• Jaine Austen Mysteries:
  • In Last Writes, Jaine has two that let her figure out that Wells is the killer and how he pulled off poisoning Quinn; hearing Marco the prop man recount stories Quinn told about his days as a valet (giving Wells a very good motive to kill him) and the warm up guy doing magic tricks (remembering Wells was a magician and explaining how he could have poisoned the doughnuts without being in the prop room).
  • Throughout Death by Pantyhose, Kandi has been trying to find an actress to go through driving school for her. Jaine scolding Kandi for hiring someone to do her dirty work for her leads her to realize Reagan Dixon did the same thing with killing Vic.
• Max & the Midknights: The Tower of Time: In chapter 1, when Max is pondering on how to find out why she and her sister Mary were separated at birth, an idea pops into her mind, sending her running to someone she figures can help: Mumblin' the Magician.
• Angela Nicely: In “Cupcake Wars!”, Angela gets the idea to decorate her brown-iced cupcakes like monsters when Maisie complains that they “look like blobby monsters”.

Live-Action TV

• The Afterparty: Danner has an epiphany about the murder in episode 7 that she explains in episode 8. After Culp brings up an old case of hers involving a woman who was murdered when she opened the door, Danner realizes that the closet door in Xavier's bedroom was closed in every story except Aniq's, meaning the killer could have hidden there and killed him before Aniq went upstairs. She quickly pieces who it could have been and guides Aniq to the same conclusion in the finale.
• Angel
  • Lampshaded when Angel announces that they're waiting for Wesley's Eureka Moment — at which point Wesley promptly shouts "Eureka!"
  • And in the episode "She", Wesley is looking through a Tome of Eldritch Lore when...
    Wesley: Aha!
    Cordelia: That better be an "Aha!" of triumph.
  • Gibbering Genius Fred puts it more poetically.
    Angel: Listen, listen, listen... What are you listening for?
    Fred: The click. When it all comes together and makes sense. There's like a click in your brain and then you understand things again.
• The Dutch Detective show Baantjer featured, in each and every episode, a Eureka moment when the protagonists were in their usual bar, when the barman makes an offhand remark. The Eureka moment always looks and sounds the same too. Eventually Lampshaded, when the barman asks if he doesn't deserve be put on the police payroll.
• This trope was regularly parodied in the Batman (1966) TV show. "That's it, Robin! The man in the grey suit was whistling the Star-Spangled Banner BACKWARDS! The Joker's lair must be in the old fireworks factory! To the Batmobile!"
• Battlestar Galactica ("Scattered"). Gaeta comes up with the idea to network Galactica's computers by lining up soap bars in the latrine.

• Bones:
  • In the pilot, Brennan is sitting down to have a drink and discussing a book written by the episode's original patsy, when they come across the patron saint of fish, and Brennan realizes who the real baddie was, based on the fact that he kept tropical fish tanks that used a certain type of diatomaceous earth, and runs off to take him down by herself.
  • "The Maiden in the Mushrooms" has a C-plot involving Hodgins using the last of Finn's late grandmother's special hot sauce and trying to recreate the recipe using the lab equipment to analyze its contents. He succeeds and Finn starts digging into the catfish that's just like his grandmother used to make, and Hodgins tells him to slow down or he'll choke on a bone. Finn says that that's not a worry with a baby catfish because their bones are too malleable. Cue realization that the victim was young enough that hanging wouldn't necessarily have snapped her hyoid bone.
• The midseason finale of the final season of Breaking Bad ends with Hank realising his brother-in-law Walt was Heisenberg all along by comparing Gale's notes to Walt's book. On a toilet.
  • Few episodes later, Jesse figures out what happened to the ricin cigarette after trying to smoke his other cigarette, and deduces Walt did poison Brock.
• Buffy the Vampire Slayer
  • In "Innocence", Xander has an idea how they can defeat the Nigh-Invulnerable Judge when Willow gripes that they need an army to defeat him (the idea is to steal a rocket launcher from an army barracks).
    Xander: Whoa, whoa. I... I think I'm having a thought. Yeah, yeah, that's a thought. — Now I'm having a plan!
    (The lights cut off)
    Xander: Now I'm having a wiggins...
• Castle is beginning to show an aptitude for Eureka Moments, usually inspired by his daughter. In a reversal, he gave one to his daughter in one episode.
  • Castle and Beckett will often have these moments simultaneously (or near simultaneously) in order to demonstrate how they click (in more ways than one). For one example, Beckett was writing something on The Big Board when she suddenly had a brainwave... and Castle at the exact same time ran in from the elevator, having obviously had the exact same brainwave.
  • Beckett has even been known to intentionally trigger Castle's Eureka Moments when she wants him to think he's figured something out by himself. One episode involves a bet between them over who will figure out the connection between the victim and suspects first. If Castle wins, he gets to stay with the team, and Beckett's not ready to admit she doesn't want him to go, so she prompts him to discover the counterfeiting operation by saying "They make a lot of money..." In another episode, she's set up an overly-elaborate surprise party for Castle, so when he hasn't quite figured out where he needs to be to advance her plot, she awkwardly asks him if he wants "a soda from the fridge" to make him realize where the "killer" could have hidden the "body."
• Charmed (1998): In the episode "Y Tu Mummy Tambien", after Phoebe is kidnapped by Villain of the Week Jeric, Piper and Paige turn to Cole for help only to find him holed up and trying to find a way to kill himself. Piper suggests he take therapy, to which Cole retorts that he'd "rather chop his head off than have it examined"... which gives him the idea to summon a guillotine and do just that. He never gets to actually use it, however, as he decides to team up with Jeric afterwards.
• Happens with astonishing regularity in The Closer. Brenda has them all the time... in fact, she had one when she was at her father's hospital bed, and another when she was trying on her wedding gown.
• Frequently used in Columbo where the detective would see something that would inspire him and would only be revealed at the end, once that critical detail had been used to lure the killer into revealing their crime unwittingly.
• Criminal Minds:
  • In the episode "Compulsion", Gideon has a friendly conversation with a student who broke up with his girlfriend for another guy. The student says that his ex told him he would suffer the wrath of God, leading to the conclusion that the episode's unsub is religiously motivated.
  • And in a later episode, Reid figures out how to get back a lost childhood memory while having a chat with a hooker in front of an automatic poker machine.
    Girl: So, did it work? Did she quit smoking? Because I've tried everything. The patch, pills...
    Reid: You should try hypnosis. They've had great results with... hmm. [gets up and walks away]
    Girl: Hey, wait, you won, like, two thousand dollars on this machine!
    Reid: [distracted] Keep it.
    Morgan: You do realize that you just gave two thousand dollars to a hooker, right? What were you talking about, anyway?
    Reid: How to quit smoking.
• Later seasons of CSI have relied heavily on episodes in which evidence gathered for one case provides the Eureka Moment for one or more of the other cases in the episode.
• CSI: NY:
  • In one episode, Hawkes watches a Jennifer Lopez video during his lunch break. While admiring her, um, assets, he remembers they are insured, helping him figure out the case — it's an insurance scam.
  • In another, Flack has to open the door to leave the room he's been in with the CSIs. Doing so makes him remember the door at the crime scene had been locked from the outside, so the killer would've had to have had a key.
• This is a staple of Death in Paradise. Towards the end of each episode, the investigation will have hit a brick wall until a seemingly innocuous object or statement from one of the others will prompt this in our British protagonist. Usually, this results in confusion from the rest of team, especially in Season 3 as Goodman tends to talk to himself while making the connection and prompting Dwayne to comment that Goodman is crazy.
• Doctor Who has it happen so many times, it's practically a drinking game at show marathons.
  • "The Talons of Weng-Chiang" makes fun of the word itself: the Doctor claims that it translates from Greek as "This bath is too hot."
  • "Forest of the Dead": The Doctor has a couple.
    • When he realizes the meaning of the Exact Words of the cryptic message: "You don't say saved, nobody says saved! You say safe!" The reason why there can be 4,022 saved but "no survivors"? They've been saved to the hard drive.
    • At the end, after River Song's death, it suddenly occurs to him to wonder why his future self, knowing when she was going to die, would give her a sonic screwdriver. The answer? Because he'd included a way to save her.
      The Doctor: Why?! Why would I give her my screwdriver? Why would I do that?
  • "Time Heist": In Karabraxos' vault, the Doctor figures out who the Architect is. As befits his Large Ham style, he strikes a nearby gong just to accentuate the moment.
    The Doctor: I hate the Architect!
  • "The Pyramid at the End of the World": The Doctor is just about to confess his blindness to Bill when it dawns on him how to figure out which lab the Monks are watching.
  • "Kerblam!": Trying to figure out how to get inside the Kerblam! warehouse complex and find the person who left a "HELP ME" message in her package, the Doctor hits on posing as new workers after Ryan, who works in a warehouse back in Sheffield, comments that the site reminds him of his workplace.
• This is also a Once per Episode occurrence on the 1975-6 Ellery Queen TV series. In the final act Ellery will be in some mundane activity, usually with his police Inspector father, say "Of course!" and break the fourth wall to ask the audience if they've solved the mystery.
• Sheriff Carter solves problems with literal Eureka Moments, followed by saving the town with an It's Up to You sequence. (Especially ironic since he's the supposedly only normal person in a town full of geniuses.) Sometimes, however, the Eureka Moment moments come from the geniuses after the sheriff suggests a Muggle solution.
• Inverted in Everybody Loves Raymond, when Ray lies that he has a great Christmas present ready for Debra, which he got the idea for on a trip they took to Manhattan a while back when she shouted "Oh my god!". On his brother's advice he gets her a First Edition copy of To Kill a Mockingbird, then has to blunder his way through an explanation of what she shouted "Oh my god" at in Manhattan that caused him to think of the book.
• Extraordinary Attorney Woo: Young-woo's flashes of insight are signaled by the scene shifting to soft lighting and a wind machine blowing her hair before fading to shots of whales or dolphins.
• In Farscape: Not so much a mystery as a scientific puzzle, but while John tries to figure out how to save Earth from the Scarrans at the end of the regular series, Aeryn tells him not to beat himself up over it. Because of the way she phrased it, he gets an idea for a solution, kisses her, tells her to "Never change!", and runs out. Aeryn gets a half-pleased, half-bemused look on her face.
• The F.B.I.:
  • In "Slow March up a Steep Hill", Ward is talking to Erskine about Erskine's daughter's engagement. He uses the phrase 'king of the hill', and Erskine suddenly has an insight into the bank robbery he is investigating and abruptly leaves the room.
  • In "Courage of a Conviction", Erskine and Jim are sticking pins in a map to mark all the locations where a notorious forger has passed forged cheques. Jim comments that the only connection he can see is that they are all major cities. Erskine says that he is certain there is something they are missing. Jim replies "Well, you play your hunch and I'll play mine. That's what makes a horse race". At that Erskine suddenly realises that all the cities marked have major race tracks and, on checking the dates the bad cheques were passed, learns the cheques were all passed around the date of major horse races at those tracks, and deduces that the forger is a gambler who follows the big money horse races round the country.
  • In "The Hijackers", Lew's uncle Walter makes a comment about how everything became worse once he retired and had nothing to fill his time. This causes Lew to rethink the case and realize that the hijack was never about the loot; it was about the company.
• The Finder has Walter Sherman having these in the middle of a Dream Sequence.
• In one episode of Flashpoint, while the team is escorting a serial killer across the border, a soldier whose daughter was one of the victims kidnaps Sam, intending to set up a prisoner exchange so he can get his hands on the killer. SRU figures out how to foil the plan and it appears they have all the involved parties in custody — until Sam gives the guy a brief Where Do You Think You Are? that references the man's service in the Sudan. Earlier in the day, Parker had been talking to a customs agent on the case about her service in the Sudan, and he quickly realizes this is unlikely to be a coincidence.
• In Fringe, due to Walter Bishop's mental fogginess, he frequently has difficulty remembering certain things. He frequently paces around and mumbles various mnemonics and unintelligible fragments of an idea until someone, often Astrid Farnsworth, happens to say something that jogs his memory.
• Corporal Agarn's abilty to inspire these was one of F Troop's many Running Gags. There would be an impossible situation, such as O'Rourke's annoying Irish father visiting the fort and overstaying his welcome. Cpl. Agarn would make a comment like "He'll never leave unless the Little People show up and convince him to go back to Ireland." Someone else, realizing this was a great idea, would say "Agarn, I don't know why they say you're so dumb!" Moments later, Agarn, Wrangler Jane, and Cpt. Parmenter would be dressed as leprechauns and sneaking into the old man's bedroom. Suddenly, Agarn would say "WHO says I'm dumb?"
• Galileo: Yukawa gets a particularly hammy one every case, involving him writing equations of uncertain relevance on the nearest available surface, while the show's guitar theme starts playing and snippets of previous scenes zoom past, and ending with him in a characteristic pose with his fingers over his face. At that point, we can be fairly certain he's figured out the case (or at least, the scientific part of it that he's interested in).
• Game of Thrones:
  • Ned has one in "A Golden Crown" when he realizes the truth Jon Arryn died for. The differences in medium (tv series vs. book) is nicely shown in this case. In the books, we saw his mental process as he realized the truth. Here, his facial expressions show viewers he's realized something, but he can't talk about it in front of his children.
  • Theon has one in "The Ghost of Harrenhal" when he considers that attacking Torrhen Square would draw out the garrison of Winterfell.
  • While explaining geography to his foreign wife, Robb realizes that his forces stand between the Lannisters and their home at Casterly Rock.
  • During a reading lesson with Princess Shireen, Davos tells her about a nearly fatal run-in he had with the First Sword of Braavos, who was working for the unbelievably wealthy Iron Bank of Braavos. This reminds Davos of the Iron Bank of Braavos, and how they have the gold to fund Stannis in hiring sellswords to make another attempt on the Iron Throne in the aftermath of Joffrey's death.
  • The moment Yara sees her uncle Euron Greyjoy at the Kingsmoot, she immediately realizes that he killed her father and openly accuses him of this.
• Spoofed in Garth Marenghis Darkplace ("The Apes of Wrath") when people start devolving into monkeys due to contaminated water. The hero suddenly puts all the pieces together (the fact that his friends turned into monkeys after drinking a cup of water, the only two people who haven't turned into monkeys aren't drinking the water, and that the water's a sickly green color) and concludes... that he's thirsty.
• The heroine of Ghost Whisperer seems to have moments like this now and then when trying to figure out the identity of the Ghost of the Week.
• On Good Eats, Alton was agonizing on what to do for an avocado-themed episode (while his assistants are suggesting varieties of guacamole) when one rolls into a sink full of water. He shouts "Eureka!" when he sees that the avocado floats.
• Parodied on The Goodies.
  Tim: But nobody could move at that speed!
  Bill: Yeah, that's... inhuman!
  Graeme: Yes... maybe that's exactly it!
  Tim: Why, what do you mean?
  Graeme: ...I dunno, I shall have to think.
• The Good Place:
  • In the Season One finale, watching her friends argue with one another about who has to be sent to the Bad Place causes Eleanor to think "God, this is torture", which makes her realize the truth: They've been in the Bad Place all along. Thanks to in-universe reboots, the first episode of the second season leads up to the same realization (though in a different context and much sooner in-universe)… and the second episode has an entire montage of them (one time with Jason being the one to figure it instead of Eleanor).
  • In the Episode "The Book of Dougs", Tahani struggles to mend Jason and Janet's relationship while Michael tries to figure out why no one has gotten into the Good Place in 500 years. When Tahani explains her situation to Michael, she claims that "There are so many unintended consequences to well-intentioned actions", which Michael then realizes is why no one is good enough for The Good Place.
• Gotham: In "All Happy Families Are Alike", Bruce and Alfred tear Thomas Wayne's study apart looking for some clue as to what he had been secretly working on. After failing to find anything, Alfred attempts to persuade Bruce that he is on a wild good chase and remarks "There are none so blind..." This suddenly gives Bruce the inspiration for where he should be looking.
• All the characters of Graduados, except the seniors and the teenagers, attended high school together in the eighties, and they are now in their forties. Unknown to them, Patricia Longo is Jimena Benitez, the fat girl of the class that everybody insulted and mocked. She got thin, she changed her name... and wants revenge. Several hints of her true identity were released here and there. And one day... a comment from Patricia left Loli pondering. She had a wave of flashbacks in the night, and got her Eureka Moment: Patricia is Jimena!
• Harrow: In "Aegri Somnia" ("Hallucinations")", Harrow is discussing Francis Chester's death (an event unconnected with the Body of the Week) with Dr. Laurie Badcoe, when Badcoe says that Chester was a dangerous beast who "died in captivity". Harrow repeats "in captivity" and experiences a Eureka Moment regarding the Body of the Week.
• Hogan's Heroes: Colonel Hogan gets most of his ideas this way. A typical scenario involves pacing while the others discuss a problem. He then pauses, smiles, and says "Wait a minute," before outlining the plan.
• In Homeland, Carrie has one when watching some musicians play at a bar and realising that Brody doing the same might be a signal.
• House does this every episode, most of the time inspired by Dr. Wilson. It's actually stated on the show that House will seek out Wilson to talk about unrelated subjects because it helps to jog his mind and inspire Eureka Moments.
  • The show isn't above lampshading it in other ways, either:
  Wilson: Who the hell chats about their blood type? You had to have tested me.
  House: (to himself) There's no reason to ask anyone their blood type...
  (House pauses, and as usual starts staring into space as if he's working something out in his head)
  Wilson: You're about to run out of here now, aren't you?
  (House gets up and leaves immediately)
  • Or, in another episode:
  Wilson: ...and you aren't even listening to me anymore, because I just gave you the solution to your case, right? And now you are going to leave without saying anything else.
  House: (as he leaves Wilson's office) No.
  • House once actually showed up outside Wilson's apartment after they'd had a falling out in the hope that if he could get Wilson talking long enough, he'd eventually say something that would give him an epiphany. It didn't work.
  • Wilson had one once as a result of noticing an obscure detail about a patient. He referred to it as a "House Moment."
  • Taub had one in an 8th season episode while being chewed out by House for not being objective about a patient. He said "... I think I just had a light bulb." House immediately stopped ragging on him and said "You can trust light bulbs."
• Happens often in House of Anubis, usually thanks to Amber.
  • The riddle was "where yesterday always follows tomorrow":
    Amber: Don't try and confuse me with your fancy words.
    Patricia: It's in the dictionary, Amber, it isn't fancy.
    Nina: [suddenly jumps up] Dictionary... of course!
  • Victor is their main enemy for this season and Corbierre (his stuffed raven) is his "pride and joy":
    Fabian: [reading riddle] Inside the core of my enemies' pride is where the final relic hides...
    Amber: Core... core...
    Patricia: You sound just like Corbierre, Amber. Coo... coo...
    Nina: Patricia, Amber! Geniuses...
    Amber: Thank you! Wait, why are we geniuses?
• iCarly:
  • In "iStakeout" when Sam mentions aside why the detectives are being lazy over getting evidence over a supposed pirated DVD guy and they should get the evidence themselves, this inspires Carly to get the idea for the gang to enter the convenience store undercover and interrogate him.
  • In the climax of "iEnrage Gibby", Gibby is about to fight Freddie on the web show after accusing him of attempting to kiss his girlfriend Tasha; when Carly brings up the rotting peanut butter and jelly sandwich from last week being recorded by the corresponding surveillance camera, Freddie realizes the camera caught footage of Tasha tripping and falling on him, and he uses such to prove to Gibby he's innocent.
• Done frequently in Inspector Morse with a inconsequential remark by Sergeant Lewis providing the inspiration for Morse to solve the mystery. In an ITV3 trailer for Sequel Series Lewis, Inspector Lewis actually refers to "that eureka moment".
• Jonathan Creek actually used this so much that at one stage another character actually anticipated that a totally random object would trigger a Eureka Moment in Jonathan, and so caused a distraction.
• Kamen Rider Build: Hearing Kazumi complaining about how Gentoku has ruined his pasta dish recipe despite having the same proportions of the same ingredients to hand makes Sento realise that the Hazard Trigger and the Evol Trigger share enough of a design that the latter likely shares the flaw Shinobu demonstrated in the former, which would allow him to paralyze Evolt in the same way.
• Played with in an episode of Kate & Allie; Kate's daughter Emma receives an ugly Aztec statue from her dad for a birthday gift, only to have various people trying to buy the statue from her or threaten her if she doesn't give it up, without explaining why they wanted the statue. At one point, Allie finally shouts, "Just take the money, Emma! The way they're chasing after it you'd think it was The Maltese Falcon!" With that clue Emma realizes that the statue must contain something valuable and breaks it with a rolling pin, revealing that the statue contained a ruby pendant and a note from Emma's dad. It turns out that the "interested parties" were friends of Emma's dad, who staged a mystery for Emma to solve, and that Allie was in on it from the beginning.
• In Killing Eve, Eve is at a dead-end when trying to track down the assassin she's hunting for. Then, while looking in the mirror and tying back her hair, she suddenly remembers the last time she did this — specifically, she remembers the young woman she met in the bathroom who saw her pulling her hair back, and told her to leave it down. This causes Eve to realize that this young woman (and, indeed any other people who were near that bathroom at the time) may have seen something she didn't. Then it turns out that the young woman is the assassin in question.
• In one Law & Order: Special Victims Unit episode involving the murder of an astronaut, the investigation is stalled, until Elliot's son makes an offhand comment that, "I'd do anything [to get to the moon]. Anybody would." This causes Elliot to realize what might have motivated the murder, which in turn (combined with other evidence) suggests the identity of the killer.
• In the Legends of Tomorrow episode "Outlaw Country", Ray realises Turnbull will be transporting his dwarf star alloy cross-country by railroad, which in turn leads him to figuring out Turnbull's entire plan, because he got a little carried away with his train of thought.
• In the Malcolm in the Middle episode where it looks like Hal is going to prison after the executives at his his company used him as their Fall Guy, he confides in Malcolm that he was terrible employee who barely did anything, and took Fridays off. When Francis is talking to Malcolm about having himself legally emancipated, and that he and Piama can take care of Jaimie and Dewey, Malcolm has a realization and needs to tell Hal immediately, but decides to wait until he's done having sex with Lois. At the trial, Hal testifies that he took Fridays off without permission, and when he's asked how's that relevant, Hal states that Malcolm figured out that the days where he was supposed to be conducting illegal pay offs, and other shady white collar crimes, were all Fridays. When asked if he could prove himself, he shows his "memory box" is full of souvenirs and memorabilia from all the places he visited on the Fridays he didn't show up for work.
• Married... with Children: Kelly Bundy once gets one of her rare moments of insight and announces it with "Urethra!"
• Classic example, from M*A*S*H; Hawkeye and BJ challenge Winchester to join them in a poker game with Col. Potter, Major Houlihan, Father Mulcahey and Radar, only to have Winchester way ahead halfway through. While Winchester is taking a break, the others complain about his annoying whistling, with Radar commenting that he keeps whistling even louder when he's bluffing. A few seconds later...
  Hawkeye: A-ha! He whistles louder...
  All: ...When he's bluffing!
• A staple on Midsomer Murders, where DCI Barnaby regularly receives the inspiration for solving the murder case from unrelated conversations, often in chats with his wife about whatever happens to be their personal side story (preparations for a county fair, talking with a real estate agent, etc.) in the episode. In one case, he was at his daughter's big play, when the moment came from one of the actor's lines. Cully goes onstage just in time to see her dad running towards the exit, knowing exactly what's happening.
• Monk: In one episode, the date on a ketchup bottle let him work out a whole case he hadn't even known existed! In earlier seasons, this frequently led to some humorous non-sequiturs, such as "If he's 37 years old, then I know how the judge was killed."
• Jessica Fletcher gets them a lot on Murder, She Wrote.
• A common occurrence with William Murdoch in Murdoch Mysteries.
  • Lampshaded in "Convalescence" when Crabtree is standing for Murdoch as acting detective. Having reached a seeming dead end in the case, Crabtree starts staring The Big Board. When Higgins asks he what he is doing, Crabtree says that whenever this happens to Murdoch, he stares at the board and everything suddenly falls into place. He then adds that it is not as easy as Murdoch makes it look and all he is getting is a headache.
  • In "The Kissing Bandit", Julia Ogden's sister is trying to explain to Murdoch that, even though Julia has settled for marrying someone else, that doesn't mean she doesn't love Murdoch, if he would only act on his own feelings, rather than resign himself to the situation. She then uses the reaction of a woman kissed by the Bandit as an example of being swept away by one's feelings.
    Murdoch: I wasn't aware I had resigned myself to anything, Miss Ogden. But you have given me some insight into this case.
    Ruby Ogden: I have? I didn't intend to.
• Parodied in Monty Python's Flying Circus. In the "Philosophers' Football Match" sketch, there is a literal "Eureka!" moment from Archimedes, who suddenly realizes that he's on a football pitch and shouts it to the heavens, before starting a quick attack in the dying minutes of the match that allows Socrates to score the game-winning goal.
• In NCIS, McGee got one while taking a polygraph test when the examiner mentioned that the regulars on her morning train were worried when they didn't see her.
• Happens in nearly every episode of NUMB3RS, with camera effects indicating the mathematical wheels turning in Charlie's head. Usually followed up with the strangely PBS-like explanation of the relevant analogy. Somewhat less common in the last two seasons, though it still happens.
  • Lampshaded at one point by Amita, who had been talking to Charlie about a break in at his house until Charlie suddenly makes a connection to the case.
    Amita: Are we not talking about the same thing anymore?
  • Larry has a literal one in "All's Fair", complete with multiple similarities to the Trope Namer. He even yells Archimedes' name in triumph as he runs across campus. In his bathrobe.
  • Don gets one in "The Janus List". Charlie is somewhat taken aback at actually seeing from an outside perspective what a Eureka Moment looks like.
    Charlie: Is that the face that I make when I...?
• Padre Coraje has a Non-Powered Costumed Hero, Coraje, who poses as the priest of the village. Clara Guerrico remembered several details about both of them, and realized his secret identity.
• In the Parks and Recreation episode "Eagleton", Leslie is struggling to overcome her rival Lindsay in the neighboring town, who put up a fence in the middle of a shared public park. Ann offers to beat Lindsay with a baseball bat, which gives Leslie an idea. Cut to a few days later, when Leslie has turned Pawnee's side of the park into a baseball field using the fence as a convenient boundary.
• In the Power Rangers in Space episode "Five of a Kind", T.J.'s watching video footage of the Rangers' last fight against The Psycho Rangers (who the Rangers have struggled badly against up to this point, as each Psycho copies their individual fighting style) when the color disappears from the video. The monochrome footage gives him the idea to disguise the entire team in the same color uniform, so the Psychos won't know who is who.
• In Prison Break, Mahone puzzles over a clue to where Michael is going that ends with the word "woods." After seeing the badge of a cop whose last name is Rivers, he realizes that the clue does not refer to a place but a person.
• Probe:
  • "Computer Logic": When Mickey tells Austin that the broken rose petal reminds her of a piece of glass, he finally makes the connection to what happened; this episode's death was caused by liquid nitrogen.
  • "Computer Logic, Part 2": Michelle tells Austin to think about who can dial a phone, but doesn't like to talk, and knows all of Austin's unlisted telephone numbers. He immediately realizes that the mysterious figure who has been prank calling him and causing the mysterious electrical behaviour must be Crossover, the Artificial Intelligence.
  • "Untouched by Human Hands": When Mickey points out that Austin can't be aware when every acorn falls, he thinks of tea. That chain of random thoughts helps him realize that there was something wrong with the tea in the radiation lab. The glass of tea in the video was full, but they sent the robot in when it was half-empty.
  • "Metamorphic Anthropoidic Prototype Over You": While decoding Josephine's writings, Austin realizes that she thinks all of reality is just like on television. Her morality is based on things like Soap Operas, where killing romantic rivals is acceptable behaviour. He immediately calls Mickey and tells her to lock down the warehouse for her protection.
  • "Plan 10 from Outer Space": Reading the letter from the lightning rod company helps Austin figure out what really happened to Truman. He tells Mickey to get the other two characters and he's going to show them who "Rexel 14" and the murderer really are.
  • "Quit-It":
    • Austin provokes Mickey into insulting Lou to figure out why the neighborhood didn't like him. One of the things she mentions is that he was reluctant to talk about children, even with his wife. At that moment, Austin realizes that the kids were in control, and responsible (somehow) for the Brainwashing.
    • Another realization hits Austin when Mickey tells him he's been listening to the same song for too long. He checks a cassette from the neighborhood for Subliminal Seduction, finding a message for him specifically.
• Shawn Spencer in Psych frequently has major Eureka Moments very early in the episode. Usually he's figured out the particularly far-fetched explanation very early (such as figuring out that a victim had been bitten by a T-Rex... don't ask), but the whole episode then revolves around him and Gus trying to find the evidence to prove the outlandish theory correct. Reverse Detective Work, maybe?
• Sam induces one in a doctor in the pilot episode of Quantum Leap. When the leapee's pregnant wife goes into early labor, Sam uses his medical training to recommend certain drugs to stop the labor. Unfortunately, these drugs do not exist in 1956, leading an air force physician to assume that he is pulling a stunt. Sam then remembers that the technique (developed in the 1960s) originally used alcohol; when he tells the increasingly irate doctor to think about what an intravenous solution of 5% alcohol and glucose would do, the doctor considers the implications and then realises that the idea is sound.
• This trope regularly occurred on Remington Steele, with Steele being reminded of an old movie which somehow resembles the case he is working on. Sometimes used as a Red Herring when Steele's movie references end up providing a plausible but entirely incorrect solution.
• In one episode of Seven Days, a scientist discovers a cure for cancer by seeing some water on her morning jog. The discovery is apparently averted when Frank goes back and interrupts her right before she sees the water — but she discovers it anyway after receiving a similar Eureka Moment from some coffee Frank gives her.
• Scrubs uses this regularly as well. JD often sees his friends solve their problem of the week and realizes this can be applied to his own situation.
  • Beautifully lampshaded here:
  J.D.: Oh, I'm just doing this thing where I use a slice of wisdom from someone else's life to solve a problem in my own life.
  Jordan: Seems coincidental.
  J.D.: And yet I do it almost every week.
  • Parodied in one episode using paint. It was a parody of House.
• Sherlock Holmes does this all the time on Sherlock.
  • "PINK!!!!"
  • A memorable example; in the third season episode "The Sign of Three", during a long, rambling best man's toast at John Watson's wedding, he mentioned a case that he was not yet able to solve, highlighting how John had helped save the life of the intended murder victim, an Army officer. At the end of the speech, when he called for a toast for "John Hamish Watson", he realized that a woman involved in another case knew John's Embarrassing Middle Name and that he was getting married, and followed that thread to uncover that one of the guests at the wedding, John's old army commander, was a target for the same attempted killer. He decides to tell John about it, and than Sherlock, John and Mary solve the case together, and John's old Army commander doesn't get killed.
• Hong Kong prime time dramas seems to love this trope. Case in point, the period drama Song Shijie, where the eponymous character is a court lawyer who seems to be surrounded by people and incidents that randomly give him pivotal clues.
• A simultaneous example occurs in the Square One TV Mathnet mystery "The Case of the Mystery Weekend". While playing a game of color 8-ball, where the player must sink balls in the order red-orange-yellow-green-blue-purple-black, George Frankly realizes that guests have been disappearing in a similar order, going by the decorations of the rooms they were assigned. Later, fellow guest and sax player Miles Reed reveals he deduced the same thing, presumably inspired by "Somewhere Over the Rainbow", the song Reed had been practicing throughout the weekend.
• Stargate SG-1. If Jack O'Neill is going to solve the episode's problem without shooting his gun a bunch, he'll say something random and Carter'll build a solution out of it.
  • The moment in Window Of Opportunity where O'Neill finally realises that he can, in the words of Daniel Jackson, do anything without having to worry about consequences.
  O'Neill: ...excuse me.
  Teal'c: <puts the chalk down, bows his head and follows Jack out of the room.>
  • When Anubis attacks Earth with a weapon that will cause the Stargate to explode, everyone is desperately trying to find a way to stop the process. Until alien visitor Jonas Quinn notes that the Stargate is much bigger than the doors to the gate room, and asks how they got it in. Carter tells him the ceiling opens, and the gate was lowered down. He asks if could go back up. She repies doing so won't disconnect the gate, and there's nowhere on the planet they can take it... This brings about the sudden realization that they don't have to shut down Anubis's weapon, they just have to get the Stargate off the planet and let it explode somewhere else.
    • Another one later in the same episode when, after O'Neill is unable to get the Stargate to a safe altitude with the X-302, he realizes that for these purposes the unstable hyperdrive is just as good as a fully functional one: it doesn't matter where the gate is sent, so long as it's not here. This hadn't even been considered as a backup plan; it just suddenly occurred to O'Neill when he ran out of fuel before reaching escape velocity.
• Star Trek: The Next Generation:
  • In "The First Duty", Picard tasks LaForge and Data to go over the flight data recorder from Wesley Crusher's shuttle to figure out what caused an devastating crash that took the life of a squadmate. LaForge is skeptical, but does it anyway. After awhile, Picard approaches them and it seems that they're coming up with the same conclusion Starfleet Academy was - no idea what was going to happen and things seem sketchy, but no concrete proof. LaForge does note that the plasma interlock on Wesley's shuttle was opened, which is extremely dangerous as it could ignite the warp drive plasma. This little bit of information makes Picard realize what Nova Squadron was trying to do — a Dangerous Forbidden Technique known as a Koolvord Starburst. Forbidden because the last time it was attempted at the Academy, all five cadets were killed.
  • In “Thine Own Self”, Troi is taking the Bridge Officer qualification test. Having failed the test three times, Troi seeks Riker for help, asking whether the test is actually an Unwinnable Training Simulation or a Secret Test of Character. But Riker tells her "I can't. As much as I care about you, my first duty is to the ship. I cannot let any bridge officer serve who's not qualified. I'm sorry." Troi then realizes that the true purpose of the test is telling whether she’s willing to send an officer to their death to save the ship, even if that officer is her friend, as she sends Holographic!Geordi to a deadly assignment.
• In the Star Trek: The Original Series episode "Court Martial", Kirk idly mentions to Spock that he might be able to beat his next captain in chess when it seems that the evidence against Kirk seems airtight and he might be punished for seemingly killing a crewmember. Spock utters "Chess..." and heads out. When McCoy finds him later, the doctor's incensed that Spock's just playing a leisurely game of chess while his best friend is in danger before Spock adds in that he just won four games in a row, an impossibility. After winning a fifth, he tells McCoy that he had been with Kirk the entire time everything had happened and that while a computer can be "flawless", something didn't add up. Winning five games in a row gave Spock the proof he needed that the computer, and thus the evidence, was tampered.
  • ...That could be thought of as a philosophical bookend paired with Kirk's Eureka Moment in "The Corbomite Maneuver," where Spock uses an analogy to chess as a way of signifying their lack of options, but then McCoy idly mentions bluffing, and Kirk suddenly realizes that an analogy to poker is much more suitable to their situation.
• Stranger Things: In Season 2, Murray tells Nancy and Johnathan that no-one will believe that they caught Hawkins National Laboratory admitting to a cover-up, even though they have a recording, because what they're covering up is too surreal. People would look for any excuse to disbelieve it. Murray gets his idea when he says that the vodka he's drinking is too strong and he needs to water it down a bit - they need to sell a 'watered-down' version of the story, where the lab is painted confessing to a far more believable crime.
• True Detective: In the first Season Finale, the protagonists try to crack the Yellow King conspiracy once and for all. Cohle says they'll need to look at the old files with fresh eyes, "like we're totally green." This reminds Marty of a child's description of her attacker as a "spaghetti monster with green ears". Digging through the files, he finds a relevant photo of a house...with a suspiciously fresh coat of green paint.
  Cohle:...Fuck you, man.
• UFO (1970): Early in the episode "The Dalotek Affair", a meteor falls on the Moon as part of an alien plot. Late in the episode, Commander Straker remembers a single word from a 10-year-old TV broadcast ("fireball") and realizes that his subconscious mind is trying to tell him about the meteor's significance.
• Ultraman Mebius has such a moment in episode 34, when watching Ryuu light a campfire by twirling a stick on a piece of wood allows him to develop the drill kick technique he uses to defeat the Kaiju Of The Week
• The West Wing has a few episodes where most of it is spent by the characters trying to come up with a solution to an apparently-impossible-to-solve dilemma until an off-hand remark leads to a novel solution.
  • One has Josh struggling with trying to determine a solution for an unfavorable rider to a long-fought-for bill that will result in a piece of land being used for strip-mining. After wracking his brains all episode without success, a chance comment from Donna about antiquated computer systems reminds him of a long conversation with the President earlier in the episode about national parks, and he comes up with the idea of using the Antiquities Act to have the President declare the region a national park.
  • Another one concerned judicial nominees after the death of a Supreme Court Justice, and the declining health of the Chief Justice. Although all the characters were unhappy that they couldn't get the nominees they wanted confirmed, it wasn't until Donna told Josh the story of how her parents got their cats (they went to an animal shelter, and they couldn't decide between two, so they got both) that he has the idea of letting the Republicans name whoever they want for the open seat, if they will accept the Democratic nominee for Chief Justice.
  • "Hartsfield's Landing" has one invoked by Bartlet upon Sam during the denouement of the overaching plot regarding the diplomatic crisis between the US and China over Taiwan. Taiwan intends to test-fire the US-built PATRIOT missile defense system while China responded by organizing a massive military exercise designed to simulate an invasion of Taiwan, the end result is over 400,000 troops on high alert around the Taiwan Strait, not including the US 7th Fleet which was ordered to the Strait by Bartlet and a second fleet en route; all this is on top of the Chinese ambassador expressing displeasure at the US continuing to sell Taiwan advanced military weapons, including the prospect of the US selling four Aegis-equipped destroyers but which the Bartlet administration refuses to roll back for several reasons (Taiwan Relations Act of 1979, the impending announcement of Taiwan holding its first free elections) and the threat of China test-firing their own missiles if Taiwan does. Eventually, word gets to Bartlet and Sam, who has been following all this from his office, that the issue was resolved diplomatically and that the fleets the US Navy sent were ordered to return. Sam elects to try to figure out how it was done with Bartlet watching: the deal was that China would stand down from the exercises and allow Taiwan to test-fire one PATRIOT missile, while the US agreed not to sell the Aegis destroyers to Taiwan for ten years (Sam had guessed five, but the gist was there). What Sam couldn't figure out was why Bartlet was seemingly willing to risk war with China when Eisenhower had balked at sending ships to resupply Quemoy and Matsu (island groups in the Strait controlled by Taiwan but less than a mile from the Mainland) back in the 1950's, plus the fact that each Aegis destroyer cost $800 million and four alone would eat half of Taiwan's defense budget and the fact that selling them to Taiwan risked China getting ahold of the advanced radar technology if Taiwan did get taken. Bartlet simply prods Sam to carry on the conclusion: Bartlet had never intended to actually sell Taiwan the destroyers, it had been a bluff designed to allow China to back down while saving face. The distinction between intention and what's actually happening had been hinted at earlier when Bartlet sees Sam make the mistake of assuming that "the US Navy is in the Strait" and "the US Navy is on its way to the Strait" are the same thing.
• Yes, Minister: During the special "Party Games", Sir Humphrey and Sir Arnold meet to discuss the possibility of a new Prime Minister, and being civil servants wish to rig the situation so they'll get the man the civil service would prefer; non-controversial, liked by both sides of the split, easily led, has no ideas of his own... as they talk, they come to the realisation that Jim Hacker would be the perfect man.
• Young Sheldon: In "An Introduction to Engineering and a Glob of Hair Gel", Sheldon is working on his engineering assignment outdoors when the wind flips the pages on his notebook. That's when he realizes that he wasn't taking wind into account when designing his bridge. Maybe when Boucher said "this bridge is in pieces" he actually meant that the wind would tear apart a bridge constructed from Sheldon's design.

Radio

• On Absolute Power (BBC), Martin's comments (usually that they should give up, or similarly unhelpful) often give Charles a Eureka Moment. Lampshade Hanging in the second episode:
  Charles: You have that ability, peculiar to the mediocre, of making the obvious statement that brings out the genius in a genius.
• Parodied in the "Store Detective" skit in John Finnemore's Souvenir Programme:
  Casterbridge: You know, all along there's been something nagging me about this case. Something not quite right about it. And it took Sloman here to make me see it. "That's the way the cookie crumbles" he said. Clumsily and for no obvious reason.

Theatre

• The SpongeBob Musical: During "Hero is My Middle Name", Spongebob tells Sandy that she's the only person in Bikini Bottom with the smarts to figure out a way to stop the eruption of Mount Humongous, then hastily adds "But no pressure!" This gives Sandy the idea to build a device to disrupt the building pressure in the volcano's magma chamber which will nullify the eruption.

Toys

• Beast Wars: Uprising:
  • During "Trigger Warnings", at the climax, Wolfang has several of these; determining that the scribbling note he found on Lidar's body says "wings post-forging", that murder victim Twirl was trying to hide her original alt-mode, and that she was a Targetmaster. Then, when it looks like everything's wrapped up, he recalls something Blackarachnia told him, that Overrun, a nerdy tech guy, introduced Blackarachnia and Twirl. Because Overrun was also a Targetmaster, and he's the one who killed Twirl.
  • Early on in "Not All Megatrons", Megatron is ruminating on the Uprising, as he thinks about his old ant-droid farm. This is when he hits on the idea of severing proto-formers from their need for processed energon by taking on beast modes.

Video Games

• Heart's Medicine tends to use this as a dramatic turning point; either at the end of the final chapter or the one just before it, with the possible exception of Season One, Allison will come to some realization from a passing remark and make a breakthrough that resolves an overarching patient storyline. Spoilers are at discretionary for the former two cases.
  • Time To Heal has Allison associate the father of a young girl, Lisa, with her own father's death when she was a child early on. As she begins clearing out with her stuff, one last look at her father's picture has her associate the bruises her father had shown before his death with the bruises on her patient, encouraging her to doubt the "autoimmune disease" diagnosis and discover the true cause; Dregen's Heart Parasites, which she manages to locate and treat through a very extreme gamble; injecting him with toxin to agitate them.
  • Hospital Heat has Allison confront her absentee mother Mathilda, who apparently requires a kidney transplant, and her stepbrother Ryan. After Ryan demonstrates the same catatonia as Mathilda when she remains unresponsive, Allison realizes that her mother's spacing out wasn't psychological, and soon after why her mother's condition isn't improving; Ruth diagnoses M Athilda with advanced Herkins disorder and prescribes conscious brain surgery. Unlike Time to Heal, the payoff isn't immediate in-universe; Mathilda is prepared quickly, but Allison needs to reclaim the hospital's sold neuro-endoscope from Queensburrow. In the meantime, the fire at Little Creek from the opening is explained as John Summers' cost-cutting, greedy former partner Victor's use of outdated ICU gear sparking it, and Allison must perform the surgery in the middle of a burning hospital.
  • The twist in Doctor's Oath is relatively latecoming, so spoiler warnings are in full effect; after losing Sophia to the overarching disease, Allison falls into a catatonic state and is interred in the psych ward, retreating into an idealized version for the chapter. As the dream collapses, and Allison comes to terms with Joe's death, her offhand comment on "rejecting anything that could really help her come back" causes her to have a breakthrough; the vaccine she tried on Sophia was rejected by her immune systems. Once the dream fully collapses, Heart rushes to save the rest of them with a risky gamble; locking herself in with the quarantine switch without a hazard suit and, without a suit, enclosing the medicine in a packet of each of her failing friends' (and her own) DNA to trick their immune systems, then quickly injecting the prepared doses. It works.
• Parodied in the first season finale of Telltale's Sam & Max: Freelance Police series. Most fans had figured out by this point who the season villain was, so at the beginning of the episode Sam is trying to figure out who the villain is. Max has to drop increasingly obvious clues before Sam finally figures it out... through a nonsensical logical leap based on the fact that he's never said the word "morning."
• In Grim Fandango, after Manny discovers a suitcase filled with tickets for the Number Nine 9 train, he comments that something about them felt off but couldn't figure out what. Once he rescues Meche, she shows him more tickets in a room and says they just "sit there". Hearing that makes Manny remember that real Double-N tickets move around on their own and fly to the person they belong to, and realizes the tickets he saw before were actually counterfeits.
• Tomb Raider (2013): After cauterizing her wounded side, the intense pain gives Lara the idea to create Flaming Arrows.
• Happens a few times in the Ace Attorney series.
  • In case 4 of the first game, you're backed into a corner, you have no proof that the witness isn't who he says he is, and it looks like you're going to lose. von Karma then says something as a joke which suddenly turns everything around: "Perhaps you would like to cross-examine the parrot for some comic relief?"
  • This trope is probably why the Edgeworth-based spin-off game makes his Catchphrase "Eureka!" He actually does get one in AAI case 2, when Zinc LeBlanc falls over the railing in the plane's cargo bay, raising the possibility that the victim was pushed to his death, and died much earlier than Edgeworth realized.
  • At several points in AAI Edgeworth will hit a brick wall with his confrontations, but then the player is reminded of past innocuous scraps of conversation, then links together half a dozen or so pieces of logic, which leads to a whole new perspective on the case.
  • Dual Destinies features Revisualization (Thought Route in Japan), which shows the character's thought process as they come up with the Eureka Moment.
  • Spirit of Justice once again features Revisualization. However, the most noteworthy moment for the game comes in the final case, where Apollo has to, on the spot, and at gunpoint, figure out how to dethrone a country's queen. First he zeroes in on Ga'ran's obsession with the Founder's Orb, and rebel leader Dhurke's comments that the Orb is the key to overthrowing her. He figures that there must be some reason that Ga'ran wants the Orb so desperately. Thinking through the possibilities, he realizes that people want the Founder's Orb because it's said to grant spiritual power, which is one of the preresequites to claim the throne under the kingdom's laws, and if Ga'ran wants it because of that, that would mean that she has no spiritual power of her own. And if Ga'ran doesn't actually have any spiritual power, then that means that Ga'ran has no claim to the throne.
• Heavy Rain: The clues start coming together in the last act for the characters (and, by extension, the player) this way.
• In Assassin's Creed II, Ezio and an ally are trying to figure out how to get into the Doge's palace to prevent an assassination plot. The friend remarks that the walls are so high, "only a bird could get over them". Ezio hears this and mutters "A bird... yes...", then runs off to ask Leonardo da Vinci about that flying machine of his...
  • Leonardo later has his own Eureka Moment after they discover that said flying machine doesn't get very far on its own. In his frustration, he throws a piece of paper into the fire, where it starts to rise from the heat, inspiring the crew to set up bonfires across Venice.
  • Bartolomeo inspires Ezio to another Eureka Moment when he realizes that they have no chance of storming Baron de Valois's fortress to rescue Pantasilea. He starts wondering if it would just be best to just give himself up, leading Ezio to his idea of disguising the mercenaries as French soldiers and pretending that he surrendered himself to get past the gates.
• Nine Hours, Nine Persons, Nine Doors,
  • In one ending, Junpei looks at Snake's dead body, whilst searching the Shower room for Clover, and notices his left arm's bone: the real Snake's left arm was in fact prosthetic. Snake is thus still alive, and Junpei slowly realizes who did it. In another route, Clover makes the connection.
  • Heck, the entire plot is based on the idea that a person being in danger and having enough of these moments can trigger morphogenetic fields, essentially allowing telepathy. Junpei gets possibly the best one, so Akane can contact him.
• Although he is no detective, Professor Layton has at least one per game.
• Persona 4: Being a murder mystery, there's one such moment. However, it's the player who has to initiate it, fitting in with the theme of "Reaching out to the Truth". At a critical moment in the case, the player is given a review of the facts (several times), and then a list of names. You get 3 tries, and there is only one right answer. Fail and the case goes cold, leading to the Bad End. But if you get it right, and Protagonist will say the name out loud, leading to the team figuring out who The Killer might be.
• Persona 5: Toward the end of the game Akechi has one while on a talk show to discuss the apparent suicide of the leader of the Phantom Thieves (whom Akechi believes he has successfully murdered), and recalls that he felt dizzy for a moment. Someone's cell phone rings, whereupon Akechi realizes that Sae, by showing him the cell phone, inadvertently shifted Akechi into the Metaverse and had him kill a cognitive replica of the protagonist. At that point, Akechi acts like nothing is wrong, but soon sets out to find the protagonist inside Shido's Palace and finish the job.
• In Dawn of War 2: Retribution, Kaptain Bluddflagg has one of these when he figures out where Big Bad Kyras is hiding in the campaign map.
  Mr. Nailbrain: Maybe we should go 'ide out on dat place dey dakka'd before. Dey won't waste good dakka, right?...
  Bluddflagg: Hold on a squig! If dat Kyras-git is anglin' ta zog da hole sektor...
  Mr. Nailbrain: Right...
  Bluddflagg: And Kyras is in da Sektor...
  Mr. Nailbrain: Okay...
  Bluddflagg: And Kyras don't want ta get zogged...
  Mr. Nailbrain: Yeah... Yeah... Right...
  Bluddflagg: And dose big humie ships won't dakka da place dey dakka'd before...
  Mr. Nailbrain: Yeah?!
  Bluddflagg: Den Kyras... would go... ta da place... dey won't dakka! ... Which is dat place!
  Beat
  Mr. Nailbrain: ...Still not following ya kap'n.
• RuneScape: During the events leading up to the destruction of the old wizards' tower, mages were baffled on how to make new teleportation spells. The Red apprentice was working on a different problem; how to increase the effectiveness of combat spells by bypassing defenses. He had an idea he thought would work, but couldn't figure out why it wasn't. So he showed it to the Grey apprentice, who had the Eureka Moment; his idea — sending the spell through a second plane with Law magic — was the solution to the teleportation problem.
• In Emerald City Confidential, Petra, a private investigator, is hired by a Femme Fatale named Dee to find her Runaway Fiancé. Petra doesn't realize that Dee is in fact Dorothy Gale until Dee mentions tornadoes.
• A meta example for Super Smash Bros.: Masahiro Sakurai gets swarmed with dozens of requests for characters to join the roster, and naturally, not everyone can make the cut. His solution to this? Let the players add who they want with Mii Fighters, complete with a variety of in-game costumes, three fighting styles to choose from, and twelve special attacks for each fighting style!
  "Now, by using a Mii Fighter, anyone can join the battle!"
• In Virtue's Last Reward, this happens to Sigma whenever he's in a tight situation and he suddenly, seemingly out of nowhere, gains the knowledge to overcome it. There's also a few moments where Sigma accuses a character of being the one who planted the bombs due to suddenly knowing who it was for no apparent reason. Turns out whenever he has one of these moments, he's remembering something that he found out through "mind-jumping", where he jumps into the body of alternative timeline versions of himself. It's stated in game that one of the things needed for accessing the morphogenetic field is danger, hence why it typically only happens when he's in a tight spot. Sigma himself also doesn't remember his mind-jumping: From his perspective he IS just suddenly knowing information he can't know. In order to play through these moments, the player them-self has to have gone through one of the paths where the information is revealed through one way or another, before going back and having Sigma remember that information in the path where it isn't.
• Mortal Kombat 9: Throughout the game, Raiden is desperately trying to Set Right What Once Went Wrong after receiving a message from his future self during the events of Armageddon, said message being the incredibly vague "He must win." After multiple screw-ups and becoming desperate enough to try striking a deal with Quan Chi when Shao Kahn launches a full-scale invasion of Earthrealm, Raiden points out to Quan Chi that Shao Kahn can only merge the realms through victory in a Mortal Kombat tournament; otherwise, he will face the judgment of the Elder Gods. As soon as those words are out of his mouth, Raiden realizes that "He must win" actually refers to Shao Kahn himself; as his invasion is considered an unlawful breach of the rules of Mortal Kombat, Shao Kahn must be allowed to merge the realms so the Elder Gods can punish him for his violation.
• Mega Man 11 starts off with this. Dr. Wily once worked on a Double Gear project with Dr. Light back at Robot University, but for whatever reason he thought the project was not necessary to continue or incorporate into his work. However, as the nightmares of his repeated losses to Light and Mega Man start catching up to him, he starts to remember this work...
  Urgh... bad memories make the worst dreams! A genius of my caliber needs sleep in order to keep his brain in gear... ...wait... that research from my youth! Yeeees...! Now I'll show you, Light!!
• Played for Laughs in Yakuza 3, 4, and 5 with "Revelations", wherein Kiryu and others observe odd happenings, recording them, and gain inspiration from them to develop new combat skills. When the feature is introduced in 3, it entails Kiryu taking pictures of an elderly woman on a scooter who got distracted by a poster of a sexy Korean actor, bumped into the rear fender of a car in front of her, and unwittingly performs a forward flip over the car. After witnessing this and taking the pictures, Kiryu blogs about it and gets inspiration for a new attack wherein he similarly flips over and dropkicks an enemy.
• A rare villainous version occurs in Final Fantasy IX with Kuja. Kuja's goal is to get the most powerful Eidolon possible in order to defeat his creator, Garland. Kuja has his lackeys attempt to forcibly extract Eiko's Eidolons, only to then see that Eiko's moogle companion, Mog, transforms into an Eidolon and kicks ass due to her wanting to protect Eiko. The scene gives Kuja an idea that will grant him a similar power. Since Trance gives people who are under extreme duress/emotion a huge boost in power, Kuja decides to let Zidane's party kick his ass in battle until Trance activates so that he can use his new powers to utterly crush Zidane and his friends.
• Game & Watch: Meta example; Gunpei Yokoi watching a bored businessman play around with a calculator.
• Civilization VI has this as a game mechanic. Completing certain actions will reward players with Eurekas and Inspirations, where the player gains a set amount of the Science or Culture needed for a Technology or Civic. These include things like building three Mines for the Eureka for Apprenticeship, which improves Mines further and also unlocks the Industrial Zone or building a Wonder for the Inspiration for Drama and Poetry, which unlocks the Theater Square.

Web Animation

• In Red vs. Blue episode "Test Your Might", the only way to unlock an alien AI is to pass a test of physical ability and 'mental clarity'. After both Tucker and Agent Carolina fail, Caboose makes one of his stupid comments, prompting Church to groan, "Jesus, that empty-headed little... wait a minute. 'Empty-headed'." At that point, Church realizes that Caboose might be Too Dumb to Fool.
• One of these happens in episode 10, "Wrip an' Vinkle", of No Evil. When Ichabod insists that the Black Tezcatlipoca should be bound by the rules of the pact formed in the second episode, "And the Raven Brought Fire", Huey comments that this one doesn't seem to know that. This inspires Ichabod to recreate the formation of the pact in miniature to bind the fragment of the Ick.
• Minilife TV:
  • In "Trouble Ian Paradise", when Chris chases after Ian in their freezer, Ian loses his grip on a mountain of ice, leaving him and Chris hanging from it. Ian says he really needs to pee, which gives Chris the idea for Ian to melt some of the ice with his urine to create a small cave for them to take refuge in.
  • In "The X-Team Attacks", after the X-Team announces their plan to execute the fighters of the 28th Legondo World Martial Arts Tournament, Chris and Ian wonder what they can do to stop them. Ian asks Jack if the time machine at Minilife Studios is fixed, but Jack says its time-travelling function is still broken and it can only teleport. After Chris realizes it can still be used as a teleporter, they get the idea to teleport to the arena and rescue the fighters in time.

Webcomics

• Revolver Ocelot experiences one in this Last Days of Foxhound strip. Of course, he is just playing dumb in order to be able to manipulate Solidus later.
• Wapsi Square: Amanda you're a friggen genius!
• In Homestuck, John figures out how to use the Alchemiter as a Merging Machine after reading about a card trick.
• The Order of the Stick:
  • A monster of some kind has planted itself outside the entrance of Xykon's lair. Xykon wants it caught alive so Redcloak can tame it. Annoyed, Redcloak complains how difficult that is, and that the last monster they had only fell asleep after eating. This inspires the two villains to defeat the beast by feeding several dozen of their own minions to it, even going as far as giving that giant crackers and celery sticks.
  • Elan has one after Roy suggests not to focus on Tarquin and Nale as part of his family and that he should focus on his figurative family instead. He decides to send a message to Julio Scoundrél, whom he had met earlier.
  • Vaarsuvius has one when complaining about how incredibly difficult they're finding it to defeat Zzd'tri.
  Vaarsuvius: This is absurd! I am making the best use of my spell resources that I am able — but how in the infinite planes of existence am I supposed to be capable of defeating a wizard who has tailored not just his daily spells but his very build specifically to defeat... ...me.
  • Towards the end of Blood Runs in the Family and for a good majority of Utterly Dwarfed, Roy spends the two arcs convinced that Vampire Durkon is still really Durkon, when in reality the vampire is possessing Durkon's body. It isn't until "Giving Up Hope" that the vampire tries to bring down Roy by bringing up one of his darkest memories. Realizing that the real Durkon would never do something that cruel, Roy finally realizes Durkon is Not Himself.
  Roy: Oh. I understand. [snaps out of Domination] YOU'RE NOT DURKON AT ALL!!
• In Ensign Sue Must Die, Spock has one. Spock Prime's reaction simply rubs the salt in the wound.
• Dimentio has one in L's Empire here.
• Taito from Consolers has one when her game starts going faster as she plays. "And why does it keep going faster now? This just makes it keep getting harder and-" "Wait a minute..." The next moment, she's ready to introduce difficulty curves to the gaming world.
• In Freefall, when Florence and Winston are discussing his difficulty with space travel, he says he'll sleep on it, and she replies "Sleep on it! That's it!" and hugs him. Winston thinks "I said something clever. I don't know what and right now I really don't care."
  • There's also Sam Starfall finally figuring out why Mr. Kornada was trying to lobotomize every robot out there. A stray remark from another robot ("No, you can't have it. That's mine") makes him realize robots have property, stealable property that would go back to the manufacturer (and thus to Kornada) if they were killed or decerebrated like that. Being Sam, he finds it brilliant aside from its excess callousness.
• In Narbonic, Dave has a particularly nonsensical one when he needs to figure out how to get back together with his ex-girlfriend. Despite his advice simply amounting to, "...Just do it!", when this triggers a Eureka in Dave Artie opines, "Somebody has to be the superintelligent one."
• A Discussed Trope in Schlock Mercenary where it's noted that great scientific discoveries are more likely to be reacted to with "Hmm, that's funny...", except for the ones that get an Oh, Crap! response. However here Kevyn gives the more traditional response, then demands a bath as per tradition.
• El Goonish Shive:
  • Tedd has such a moment when he realizes that the only way for Elliot to stop getting spells themed around turning into a girl is for one such spell to accurately reflect who he is. Magic is trying desperately to give him a spell that reflects his personality, but the gender bending, which is the one thing it is absolutely sure about, is also the one part it is getting wrong.
  • After having her clothes spontaneously grow back to full size off her shrunken body, Grace is able to figure out how magic's change gave her the ability to transform her clothes. She then proceeds to follow tradition by shouting "Eureka" and running around naked.

Western Animation

• Arcane: Viktor has a violent attack while experimenting with Hextech late at night that causes him to cough up blood and collapse. When he returns to the lab, he notices first that the Gemstone he was working with has changed color, and then his blood splattered on the table. This helps Viktor realize that it can react to organic matter.
• After Saying Too Much to Jérémie, Code Lyoko's fake-Franz Hopper's words give the young genius the clues to find that Franz couldn't possibly have known that "[he] was the one who let XANA destroy [Franz's] diary," flashing back to an earlier episode about it. Nice job, XANA.
• In Batman: The Animated Series, virtually every conversation Batman has with Alfred while pondering the crime du jour leads to a Eureka Moment (and an "Alfred! You're a genius!" declaration, and a bemused "Of course, sir" response).
  • In "What is Reality?, Batman and Alfred are staring at the Riddler's latest riddles and Alfred makes the comment that the riddles all involve numbers. From that, Batman turns the numbers into Roman numerals and then simultaneously, both declare, "Of course! The Department of Motor Vehicles!" (suddenly seeing the Roman numerals DMV together could easily be a Eureka Moment for any American.)
  • "Off Balance" has Batman deducing where Count Vertigo's hideout is when Alfred tells him that he soon won't know his right hand from his left. Yes, he was confused about which direction Vertigo escaped in because his senses were scrambled, and he had actually gone in the opposite direction Batman had originally thought.
  • In "Vendetta", Batman realizes the nature of his foe due to Alfred's offhand comment that he was going to keep dinner in a Crock Pot to keep it warm.
    Batman: Alfred! You're beautiful! [dashes off]
    Alfred: Imagine if I'd gotten around to telling him about the salad.
• The Batman has some moments like its predecessor, as well.
  • In "The Clayface of Tragedy", Bruce deduces the true identity of Clayface after saving Alfred from being attacked by a sample of the clay.
    Alfred: Nasty puddle of putty, wouldn’t you say?
    Bruce: Putty…
    Alfred: Sir?
    Bruce: Joker’s Putty formula. What if Ethan was infected? Clayface was first seen in Ethan’s neighborhood, and Ethan’s been at odds with Chief Rojas. Ethan… is Clayface.
• In Arthur, Buster Baxter solved a case involving missing quarters thanks to a comment from Alan, a.k.a. "Brain".
• Dexter's Laboratory:
  • In "Dexter's Rival", Dexter has an internal conversation with himself after Mandark, who had forced him to shut down his lab, asks for him to set him up on a date with Dee Dee, leading to Dexter getting an idea for revenge.
    Dexter 1: (Appearing on Dexter's right) No way! You don't owe that jerk any favors!
    Dexter 2: (Appearing on Dexter's left) That's right! He made you shut down your lab!
    Dexter 3: (Appearing below Dexter 1) He's right!
    Dexter 4: (Appearing below Dexter 2) Yeah!
    Dexter 5: (Appearing over Dexter's head) And besides, Dee Dee is hyper and clumsy, and she would probably wreck Mandark's labor- (All six Dexters go wide eyed before adopting a sly look)
  • In "Figure Not Included" Dexter is down because some kids made fun of him for not having the new Major Glory action figure, to which Dee Dee comments that he should just make his own.
    Dexter: Make my own doll?! I am just a little boy! Doll-making requires specialized tools and equipment, hi-tech machinery! In order for me to make a doll, I would need...(beat, before his eyes narrow wickedly) ...a laboratory. (Gives off an Evil Laugh)
• Dragons: Riders of Berk:
  • While Hiccup is trying to get the other riders out of the Death Song's amber, Fishlegs tells him that blunt force or cutting won't work, since the hardened amber is tougher than anything they've seen. Hiccup then realizes that since the Death Song spews the amber in a liquid state, heating up the amber will weaken it enough for the others to break free.
  • A blinded Astrid is stuck on the sidelines listening to the others try and fail to tame a Triple Stryke. By doing so, she realizes that the Triple Stryke communicates by clicking its pincers, so she clacks two of Stormfly's spines together to replicate the noise. This succeeds in calming the Triple Stryke down long enough to approach it.
• The Simpsons:
  • In "Funeral for a Fiend":
    Millhouse: My feet are killing me.
    Lisa: Feet... killing... We have to save Bart!
  • Used on several of the earlier Sideshow Bob episodes, with "Big shoes to fill" and "Tonight on MacGyver" being two of the phrases that trigger Bart to figure out Bob's evil schemes.
  • Not to mention, in "The Great Louse Detective" (where Sideshow Bob is the detective for once and Homer is the would-be victim), he discovers who's trying to kill Homer after Chief Wiggum mentions the work a mechanic did on the parade float. He then flashes back to the wrench that was used to prevent Homer from escaping a sauna and the oil fingerprint on the invitation letter to said sauna, as well as the mechanic that he and Homer had met earlier.
  • In "And Maggie Makes Three", several people congratulated Homer because Marge had become pregnant (with Maggie). Homer, himself unaware of the pregnancy, misinterpreted these comments (even the ridiculously direct ones) as regarding his new job.^note That's "ridiculously direct", as in "Hey, Homer, way to get Marge pregnant!" "This is getting increasingly abstract, but yes, I do enjoy working at the bowling alley" Then Maude congratulates him on the new job, prompting Homer to respond, "New job? MARGE IS PREGNANT!?"
  • When the family is trying to figure out a way to keep Apu from being deported during "Much Apu About Nothing", Abe mentions he could try living in a balloon. Lisa exclaims "That's it!", leading Bart to declare that she's as dumb as him. She explains that she connects Abe being a grandfather with grandfather clause, with his statement being irrelevant.
  • In "Milhouse of Sand and Fog", when Bart and Milhouse's scheme to end Kirk and Luann's rekindled romance backfires horribly, resulting in yet another marriage crisis between Marge and Homer:
    Lisa: Mom and Dad have a marriage on the rocks, and they need to work through it in therapy to make sure it doesn't shatter.
    Bart: Rocks... shatter... jagged cliff... Lis, you've just given me an idea for the most insane, hair-brained, fool-proof scheme ever!
    (Lisa groans in exasperation)
• Captain Flamingo runs on this trope. Every use of the eponymous character's "Bird Brain" is either this, or a full-on I Was Just Joking, depending on which would be funnier. Either way, it's played for laughs, as the ideas he gets are usually ridiculous... but always manage to work.
• According to Animaniacs, Albert Einstein has conceived his famous mass/energy equivalence formula (you know, E=mc^2) while watching Wakko writing "Acme" backwards (his "a" looked like a "2"). In a similar episode, the Warners were cleaning Beethoven's chimney (badly, of course) and humming an obnoxious tune that went a little something like "Hm hm hm hmmmmmmmm". As they're leaving, ol' Ludwig finally has the inspiration for his Fifth Symphony. The next house on the Warners' route is "that Van Gogh grouch again", and Wakko picks a sunflower to help cheer him up.
• In an episode of The Raccoons, Cyril is accused of stealing a gem during a blackout. Bert is trying to solve the crime but is stumped until he sees Cedric drop his Opaque Nerd Glasses in the river. It's then that he realizes that the gem was not stolen but knocked in an aquarium, and was rendered invisible by water refraction, same as Cedric's lenses.
• Alternative Character Interpretation of Pinky and the Brain says that Pinky has one of these every time Brain asks him "Are You Pondering What I'm Pondering?", but since Pinky's thought processes are rather unique, neither the audience nor the Brain can figure out what Pinky's talking about.
• The Adventures of Jimmy Neutron, Boy Genius had a recurring delayed reaction to this. When the heroes have exhausted all their obvious options, Jimmy starts thinking about the episode's events. One completely ordinary-seeming event would pop into his mind, he'd shout "Brain Blast!", and he'd come up with a solution based on that event.
  • A similar thing happens in Chico Bon Bon: Monkey with a Tool Belt whenever Chico panics and a character suggests that he needs to take a Banana Break.
• Spoofed in an episode of Johnny Bravo where Johnny's enlisted the help of Adam West to find his missing Momma. They stop for lunch at a Chinese restaurant and West interprets his fortune cookie message ("Your heart's afire"), via Batman (1966) logic, to mean that Momma Bravo's being held prisoner at the golf course.
• South Park:
  • Sent up in a Running Gag in "Cancelled". The astronomer investigating Cartman's satellite dish implant draws several correct conclusions after increasingly absurd free association sessions based on conversations with Chef.
  • In "The Entity", Mr. Garrison struggled to invent a new vehicle until Mr. Hat commented "Boy, that Enrique Iglesias can sure gyrate his hot ass around" and decided on a gyroscope.
• Kim Possible:
  • Shego's mockery of her evil employer Dr. Drakken often gives him inspiration for his next plot to Take Over the World, such as when he decides to go on the offensive against Kim Possible.
  • When Kim visited her cousin Larry, he commented that Monty Fiske, the archeologist they had assisted earlier, was a master of Tai Shing Pek Kwar or Monkey Kung-Fu, prompting Kim to realize that he was the villain Monkey Fist.
  • Ron lapses into one when Kim mentions "Homefield" in "Ill Suited".
• From Teen Titans episode "The End 3"; Starfire, Beast Boy, and Cyborg are being beaten senseless by their Evil Counterparts:
  Beast Boy: Dude! I had no idea I was this tough!
  Cyborg: You're not! I could kick your butt any day of the—
  [beat, as they all figure it out]
  Starfire: If we cannot defeat ourselves, maybe we can defeat each other!
  Beast Boy & Cyborg SWITCH!
  [they tag hands, they swap enemies, fight starts again, they make short work of the villains]
  Cyborg: Told ya I could kick your butt!
• In Teen Titans: Trouble in Tokyo, Starfire's offhanded use of the word "fear" reinvigorates Robin's belief in trouble brewing in Japan. Now, if only it hadn't happened when they were about to kiss.
• The Samurai Jack episode "Jack vs Aku" starts with three of his attempts on Jack's life failing even worse than they usually do. The villain curses the shoddy attempts by the robots, slumps in his throne, and mumbles, "Guess it's true what they say, you want something done right, you gotta do it yourself..." Then his eyes open wide as he gets an idea (lure Jack into a trap by challenging him personally), which kicks off the episode's main plot.
• Lampshaded in the Futurama episode "That Darn Katz!":
  Farnsworth: Amy, technology isn't intrinsically good or evil. It's how it's used. Like the Death Ray.
  Amy: Maybe you're right. I guess science has to keep pushing forward, with the hope that... That's it! Pushing forward. Professor, I know how to restart the Earth!
  Farnsworth: Pssh. You can't suddenly know something by assembling a committee of words... That's it! I'll assemble your committee!
• In Kung Fu Panda, Po opens the scroll containing the secret to limitless power and kung fu itself to find nothing but a blank, reflective foil, which seems to imply that obtaining limitless power is impossible. He then meets his father who says that the secret ingredient to his popular "Secret Ingredient Soup" is also nothing; it's special because people believe it is. This leads Po to having his Eureka Moment: that limitless power resides within oneself (hence the reflection), and that "there is no secret ingredient".
• Finn from Adventure Time has one in which the word "RENCE" on one half of a murder weapon makes him think of Clarence, whom he had met several minutes prior.
  Jake: "Rence"?
  Finn: Some Donkus's real name must have been.... ReeeeEEEEEEEEEEEEEEENCE?!?!
  • In "Apple Thief", Finn solves a case when he's tipped off by the sentence, "This place could use a scarecrow."
• Terrytoons' TV character Tom Terrific will usually get a Eureka Moment when Mighty Manfred the Wonder Dog says something off the cuff to try to weasel out of a situation. In "Go West, Young Manfred," Tom is looking for a way to get back to the settler with his cap full of gold:
  Manfred: Please, Tom. Don't saddle me with your problems.
  Tom: Saddle. Pony. Pony Express! That's it, Manfred! We'll go by Pony Express!
• The Powerpuff Girls (1998):
  • In "Mommy Fearest", after the girls are grounded by the Professor's new girlfriend Ima Goodlady, Blossom gets a call from the Mayor saying that Sedusa is robbing him of his jewels. There, Blossom puts the pieces together about this coincidence and deduces that the two of them are one and the same and it was all part of Sedusa's scheme to keep them away while she committed crime.
    Blossom: Don't worry, Mayor. We'll catch Sedusa... as soon as she gets home.
  • In "Bought and Scold", Princess become the new Mayor and gets the Powerpuff Girls out of her way by legalizing crime and criminalizing crimestopping, leading Bubbles to lament "We have to be bad if we want to be good". This gives them an idea to get things back to normal: robbing Princess blind so she can repeal the law to get them recover everything before her father finds out (and she can't have them arrested either, because crime was still legal when they committed the theft).
  • In "Mime for a Change" after Bubbles is unable to save her sisters from Mr. Mime's silent colorless world, the narrator asks her what she is going to do now; Bubbles immediately replies, "I've got it!", and proceeds to unleash The Power of Rock to restore all the colors.
• In one episode of Johnny Test, Johnny gets the smart idea to shrink the clutter in his house to microscopic size because:
  Dukey: You got all of that from me saying "little".
  Johnny: Yeah, that's right.
• A minor example: in the Steven Universe episode "Log Date 7 15 2", Peridot spends much of the episode trying to understand why Garnet enjoys being fused all the time. She ultimately figures it out when it's put in the terms of her favorite Earth TV show:
  Garnet: I'm Percy and Pierre.
  Peridot: ...oooooh!!!
  • In "The Trial" Steven has been brought to the Gem Homeworld to be put on trial for Rose shattering Pink Diamond. While trying to prepare his case, the Zircon defense attorney is exasperated to learn that Steven doesn't really remember what happened way back when- and realizes that the reason he's being put on trial at all is because the official story has glaring contradictions.
    Defense Zircon: ...You don't know how it happened. I get it. There's a reason why they want you to explain how you did it. It's because it doesn't make sense!
    • Then again, the real story manages to explain how no one else was able to actually know how Rose Quartz got close to Pink Diamond: Rose was Pink Diamond all along! The only one else who knew about the real story was her Pearl, the one who sided with the Crystal Gems.
• In SpacePOP, Rand not disposing of his trash properly inspires Athena to dress the band up as garbage workers to bypass Geela's fleet.
• In Beast Wars "Code of Hero", an early human picks up the makeshift hammer Dinobot made with a stick and a stone. He is at first surprised when he uses the hammer to easily split open a coconut. Then the same giant snake that consumed another early human at the beginning of the episode lunges at him. He instinctively kills the snake with the hammer. He then holds the hammer aloft and yells in triumph as he realizes what tools like the hammer can do.
• In the Super Friends Grand Finale "The Death of Superman", the Super Powers Team (the rethemed Superfriends) visit the Fortress of Solitude to put Superman's items in order after sending his body into the sun. As they do, they're aided by a Superman robot who gives them a brief tour. At one point, the robot mentions that Superman had developed a technique to slow down Kryptonite poisoning. Firestorm, who had been with Superman when he had died, realized Superman had been in that same position when he found him. This makes the team realize Superman wasn't dead and they rush to rescue him from the sun and revive him.
• In the Teen Titans Go! episode "Video Game References", the Titans are all put in simulations parodying video games. Beast Boy's is a parody of Frogger, where after several failed attempts to cross the road, he thinks about the words "cross the road" and decides that it'd be easier to cross as a chicken, so he turns into a chicken and is able to cross without getting run over... only to get eaten by a gator.
• In the Adventures of Sonic the Hedgehog episode "Tails New Home", Sonic tries to find Tails a home (due to Sonic's concern for Tails' well-being after the latter gets injured as a result of Scratch and Grounder) and he eventually finds Tails' real parents... or so he thinks, as right after Sonic leaves Tails, it's revealed to be a trap set by Robotnik. Meanwhile, Sonic gets depressed over Tails being gone and has a flashback to when they first met and Sonic gave him the nickname Tails due to him hating his real name Miles, and then after remembering Tails' "father" saying "Tails belongs with his own kind", he then realizes that if those were actually Tails' real parents, that they would've called him Miles, not the nickname Sonic gave him (since they'd have no way of knowing it), and Sonic then immediately springs into action to save Tails from his fake parents and Robotnik.
• Invoked and subverted on BoJack Horseman. BoJack complains about how unrealistic mystery stories are and wishes he could get a random detail of his own that would help him connect the dots. When Princess Carolyn mentions Matthew Perry, it makes BoJack recall a moment with Hollyhock where they talked about the time Matthew Perry hosted SNL and starred in a skit called "Chandler's List." Instead of everything immediately falling into place on its own, the mention of Matthew Perry is what motivates BoJack to do the dirty work himself of finding out who Hollyhock's mom is.
• In DuckTales (2017)'s Grand Finale, "The Last Adventure!", Bradford has the Duck-McDuck family on the ropes as he has Scrooge bound to a Magically-Binding Contract that states that Scrooge can only have his family if he gives up adventuring. As Bradford attacks the Ducks, the triplets get the contract and look it over. It seems iron-tight until Louie mentions that Scrooge can only get his family if he gives up adventuring. It makes everyone realize that there was a loophole in the contract - Scrooge can't give up adventuring for his family because "Family is the greatest adventure of all!" Bradford thinks it's the stupidest thing ever until the contract disintegrates.
• Used twice in the Rocko's Modern Life episode, "Wacky Delly":
  • First, after ending production on Meet the Fatheads, Ralph wants to create an artistic masterpiece. However, his network contract states that he has to make one more show before they can let him go, but he has no ideas. When he tells this to Rocko, Heffer, and Filburt, Heffer suggests that Ralph's new show be about deli meats. Filburt says that idea is so bad, it'll get Ralph kicked out of his contract. When Ralph hears this, he decides to go with Heffer's idea.
  • Later in the episode, Wacky Delly becomes the newest hit animated series despite both Heffer and Filburt's creative differences for the pilot episode and Ralph's attempts to sabotage it. At one point, Ralph hears Rocko and his friends inside the editing room after having completed the latest episode, specifically Filburt say saying that turning the light on would expose the film. This prompts Ralph to open the door, and for good measure, bring along a searchlight to ensure it's overexposed. Like every other sabotage attempt, it just makes the show more popular.
• Hoppity Hooper: When Uncle Waldo got an idea how to make profit or execute a Zany Scheme, he'd make several funny poses, accompanied by mechanical sound effects.
• Bob's Burgers: Louise has one regarding the therapy doll killer while discussing Old Yeller with Millie.
• Star Trek: Lower Decks: In "Terminal Provocations", while Rutherford and Tendi are running from Badgey, Tendi takes the time to compliment Rutherford on Badgey's programming, saying that he is amazing even if he is trying to kill them. Rutherford then notes that it is weird that Badgey hasn't murdered them yet, and they finally notice that he is just as exhausted as they are from running. Rutherford realizes that he is being affected by the physical conditions of the simulation even though he shouldn't be, and if they can tire him out, they can probably freeze him out too, and changes the simulation to a blizzard to try freezing him to death.
• In the climax of Over the Garden Wall, the Beast offers to save Greg if Wirt becomes the new lantern-bearer.
  The Beast: (distorted) I'm trying to help you.
  Wirt: You're not trying to help me! You just have some weird obsession with keeping this lantern lit! I-It's almost like...your soul is in this lantern.
• The penultimate episode of The Owl House sees Luz undergo this on a personal level. "For the Future" sees Luz truly realize what it is that she's always wanted her whole life. Understanding, specifically understanding from her mother. After Camila assures Luz that it's okay to fail and to embrace her nerdy nature, with Camila stating that her own greatest failing as a parent was in ever trying to surpress that side of Luz. Thanks to Amity explaining that the thing she wanted was something abstract, specifically freedom, that caused her to bond with Ghost, Luz's own Palisman Stringbean awakens at that moment with Luz herself voicing that she can't believe it took her so long to realize that was what she had always wanted for so long.
  • This is also a huge psychological breakthrough moment for her as it directly addresses the root causes for her extreme self-loathing, first talking her Guilt Complex by emphasizing that life is all about making mistakes and learning from them with her mother finally acknowledging to Luz's face not just that Camp Reality Check was a mistake on her part but also why it was, and two the fact that Luz has in some way been rejected by literally every person she has ever met prior to meeting Eda, so hearing another human being particularly her mother not just accept but outright praise all of her weird eccentricities especially when combined with Camila’s admittance of guilt is incredibly healing for Luz’s mental health.
  • Despite having made a Found Family, True Companions, and a Loving Girlfriend, with people who love her for exactly who she is, none of them are human and thus can’t quite grasp some of the difficult intricacies in Luz's struggles in her life in the Human Realm the way that Camila can, the same way Witches and Demons can understand her in ways that humans can’t (Camila for example clearly can’t see what’s so appealing to Luz about the Boiling Isles, at least at first.) Luz had the latter the entire series, but she needed the former to be psychologically whole, especially after all the trauma she’s been through, trauma that even in the best cases would exacerbate a person’s underlying psychological issues.
• Ready Jet Go!: In "Sounds Abound," after Sean sees his friends making music with cooking items, he realizes how he can perform his sound experiment. He even shouts "Eureka!" followed by "Whatever that means."
• Work It Out Wombats!: In "Racecar Wombats," when the racecar starts falling apart, Malik realizes the solution to the problem; the wombats should take the car apart, bring all of the individual pieces through the door, and then reassemble the car outside.
• Justice League: In the episode "Comfort and Joy", the Flash sets out to find a DJ Rubber Ducky toy as a Christmas present for the kids at the Central City orphanage. The problem is that the toy is so popular that every store the Flash visits is sold out. At the last store he tries, he sees a display for Santa's Workshop in the window. This inspires him to "go to the source", running to Japan to get a toy from the manufacturing company.
• Danny Phantom: In one episode, the Guys in White have taken over the Fenton lab and kidnapped Sam and Tucker in a plan to attempt to destroy the Ghost Zone. To access the Fenton ghost portal, they need a password, and the interrogation leads to this exchange.
  Operative K: Says who
  Tucker: Says me!
  Operative K: Says me... says-a-me, open sesame!

Real Life

• The word "Eureka" originates from ancient Greek, meaning "I have found it!" Archimedes was consulted to figure out how to tell whether a crown that the king had commissioned was made from the pure gold he had supplied to the jeweler, or whether the jeweler had substituted silver for gold to make a crown the same weight. But Archimedes couldn't damage the crown in any way to do so, and as the crown was such an odd shape, he was unable to math it out. When Archimedes took a bath, some of the bathwater overflowed the edge of the tub, prompting him to realize that an object displaces its equal volume in water; and knowing that equal volumes of gold and silver have different weights, he now knew how to differentiate between an all-gold crown and a gilded silver one. Jumping out of the water, Archimedes shouted "Eureka!" and ran to report this discovery to the king. Naked. The subject of volume displacement in physics is, fittingly enough, known as "Archimedes' Law" because of this. (A Ted Talk presents an alternate theory that the project was building a massive ship, as "crown" and "keel" sound similar in Greek. See the video.)
• Just in general, this is Truth in Television. It's been proven that people are more likely to reach an answer they can't think of by not thinking about it directly. Typically happens when you've forgotten something, when you're trying to think of an answer to some hard crossword, or something else mundane. If you're really struggling to think of it, then sitting back and thinking of other seemingly unrelated things has been shown to result in what you were looking for bubbling up.
  • Sometimes referred to as the "Toilet Moment" or the "Bed Eureka", due to this typically happening to people when they're on the toilet or trying to sleep. The reason being that people typically don't have anything to do when doing either of these things so their mind wanders, and somehow finds an answer to something or some sort of inspiration.
  • And the toilet and the bed aren't the only times when people are in this state of mind. There are others, like going to the fridge for a snack, and such is the inspiration for our very own trope titles Fridge Logic, Fridge Horror, and Fridge Brilliance. The idea is that when you're realizing how insightful something really is, or how it doesn't make quite as much sense as it should, either way it often comes in a Eureka Moment a few hours or minutes after the fact.
• Newton's understanding of gravity supposedly came after an apple fell on his head. (Which never actually happened, but nobody cares about that.) The accepted explanation is usually that he came up with the law while thinking about apples falling from trees (or perhaps even saw an apple fall to the ground), but the story about one actually falling on his head is just fluff. Newton himself told this version later in life.
• Friedrich August Kekule allegedly realized the structure of the benzene molecule after dreaming about a snake biting its own tail.
• A similar tale surrounds the invention of the sewing machine: the inventor dreamed of spears with holes in them stabbing towards him, and realized upon waking that the eye of a needle to fit into a sewing machine had to be in the tip.
• Supposedly, Eli Whitney came about the idea of the cotton gin by watching a cat wash itself.
• According to IMDB, composer Bill Conti had a rocking theme all ready for the Training Montage, but couldn't figure out what to call it. Director Avildsen, impressed by the nameless piece, agreed that "It should be almost like Rocky is flying now."
• Isaac Asimov has a famous quotation where he points out that, despite the example of Archimedes, great scientific discoveries are usually not heralded by "Eureka!" but instead with "Huh. That's strange..."
• Gauss once wrote in his diary "EYPHKA^note Those are actually the Greek letters epsilon-upsilon-rho-eta-kappa-alpha, transliterated as E-U-R-E-K-A! num = Δ + Δ + Δ," thinking he'd proven Fermat's famously unproven polygonal number conjecture (yes, that's right, he did it more than once) for n = 3; he later realized that the proof in his head needed significant ironing out, but for an open question, he got it quickly enough.
• Such a moment is largely responsible for Sir Andrew Wiles' proof of Fermat's Last Theorem. His original attempt at a proof, during the formal checking, was found to have an error in one particular area. Wiles spent nearly a year trying to work out the error but was having no luck, even with help from fellow mathematician Richard Taylor, and was thinking about giving up when he had a sudden revelation regarding two of the mathematical techniques he was trying to employ and how they could shore up each other to provide the key to working out the error. This led to the revised proof which was accepted. Wiles was quoted as saying that he was so gobsmacked by the realisation that he stared at his notes for a good 20 minutes and kept coming back to his desk throughout the day to make sure that everything was still there and not just a figment of his imagination.
• According to Cognitive Psychology, when it comes to problem solving those "Eureka Moments" are actually called insights which are deep, useful understandings of the nature of a problem. However, compared to the typical slow approach to a problem solution, insights often occur abruptly and almost without warning. Tasks that involve insight usually require something new and non-obvious to be done and in most cases they are difficult enough to predict that the initial solution attempt will be unsuccessful. This can lead to the so called "AHA-experience" where the solution pops up all of a sudden.
• Merv Griffin came up with the name of his popular quiz show Jeopardy! after a network exec told him that the show, piloted under the name What's the Question?, needed "more jeopardies".
• A Eureka Moment is what inspired J. K. Rowling to write the entire Harry Potter saga.
• During the Apollo 13 mission, NASA engineers needed to make the Command Module's air filters fit the incompatible slots of the Lunar Module. The solution was devised by a engineer while he was driving to work. The film dramatization split this between an entire team of engineers, but that doesn't make it any less awesome.
• In the late 90s, a few sitcom producers came up with pilots for Fox. The most promising one was about a group of teenagers growing up in The '70s. But there was a problem: their choices for titles all had possible legal issues. After a test screening, one member of the survey group gave them their title by saying "I loved That '70s Show."
• After people started writing apps which made phone screens bright white so they could be used as flashlights, someone realized: "Wait, you know the camera flash? Why don't we just give it an on-switch?", and a much more practical flashlight app was born.
• Bob Gale got the idea for Back to the Future when he visited his parents and looked through his father's high school yearbook, learning his father had been the class president. Remembering his own high school class president, who was somebody he didn't care for, Gale wondered if he would've been friends with his father had they gone to high school together.
• Go Nagai got the idea for creating Mazinger Z after getting stuck in traffic one day and wishing for a way to get around.
• "Stone Cold" Steve Austin got his nickname this way. He was trying to come up with a nickname he could use to reflect an ice-cold stoic badass character, but kept proverbially hitting his head against the wall, unable to come up with anything. Just before he was about to give up, his wife made him some tea and told him "drink it before it gets stone cold." A moment later, both Austin and his wife looked at each other and realized what they'd just come up with.
• The Marvel Cinematic Universe got started this way. According to the Building a Cinematic Universe documentary, when Marvel Studios was first created, one of the first meetings featured a discussion of which properties they still had the rights to. As they listed off the properties they couldn't use at the time (Spider-Man, Daredevil, The Punisher, Ghost Rider, Fantastic Four, X-Men, Blade...), they slowly realized they still had the rights to most of the various characters who formed The Avengers.
  • This trope helped solved a hurdle in making Ant-Man and the Wasp: Quantumania: the writers were having trouble in trying to figure out how to get the heroes to the Quantum Realm and meeting Kang and how he would recognize them. They soon remembered they had unwittingly given themselves an answer from back in Ant-Man — Darren Cross, who was seemingly shrunken into nothingness in the climax.

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