Bat Deduction

Batman: Pretty fishy what happened to me on that ladder.
Gordon: You mean, where there's a fish, there could be a Penguin.
Robin: But wait! It happened at sea! See? "C" for Catwoman!
Batman: Yet — that exploding shark was pulling my leg!
Gordon: The Joker!
O'Hara: It all adds up to a sinister riddle...Riddle-er. Riddler?

— Batman: The Movie

When unraveling a mystery or trying to push the plot along, a character may come to an affirmative conclusion through deductive reasoning, even though the rationale behind it feels like a mental Wiki Walk that has little basis in the information as presented. This conclusion is often shockingly accurate despite lacking a naturalistic revelation, since the writer just needs to move the story along. Can also be interpreted as "batshit crazy deduction."

Often used in cases where the viewers already know that everything's connected and how they connect, but there's no in-story explanation, and the plot really needs to get to the next part. There's also the matter that since most authors are not themselves genius detectives, in many cases they have trouble thinking of a good way for the character to figure out connections that the author has already decided will exist.

Detective novelist Ronald A. Knox discouraged the use of this in his rules for a Fair-Play Whodunnit.

Consider too that sometimes the insanity of the train of thought may be required when dealing with someone who has their own unique viewpoint. In this situation it is not a matter of determining a clean and coherent legal case to back up your claims, but seeking to understand the mindset of the person who created the mystery in the first place.

The Trope Namer is Batman, specifically the '60s Adam West Batman, who, given his title as the World's Greatest Detective, can easily fall into this when a writer gets into a rut (or is playing it up for laughs). When up against criminal masterminds such as the Joker or the Complexity Addiction of The Riddler he would often rely on insane rationale or some oddly perfect analysis tool to figure out the next step in the scheme.

Compare the following tropes:

• Conviction by Contradiction: A fact stated by the accused that is revealed to be mistaken, no matter how minor, be it a single second off in the time they say they did something in their alibi or talking about the deceased in the past tense allegedly too soon after they died, is portrayed as "the clue"
• Conviction by Counterfactual Clue — the conclusion is based on faulty deduction and false or unreliable facts, which would not be legally valid
• Clue, Evidence, and a Smoking Gun — the last clue is a Smoking Gun, making the previous ones redundant
• Entertainingly Wrong — the facts and logic are broadly correct but the conclusion is way off the mark
• "Eureka!" Moment — the deductive leap is instigated by something unrelated, but is merely the catalyst for the missing piece and not vital to the logic itself
• Insane Troll Logic — the "deduction" is an excuse to reach a pre-desired conclusion
• Right for the Wrong Reasons — the conclusion is correct but the logic or facts are mistaken

Also see Only the Author Can Save Them Now. This is a natural result of having Super-Intelligence. Epileptic Trees are fan theories that look like this, and the Conspiracy Theorist is frequently someone who thinks they have pulled off the equivalent of a Bat Deduction that proves their beliefs. Gambit Roulette is the plan equivalent.

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Examples:

Anime & Manga

• This is a key feature of Case Closed, owing to difficulty translating. In the original Japanese version, an unfortunately large number of clues rely on Japanese puns and cultural references that can't really be translated, so non-Japanese readers/viewers can't fit the clues together. Though the case involving Kan'o (spelt using the characters 'ka' + 'n' + 'o') referring to the person Kano (spelt using the characters 'ka' + 'no') was easier to solve for Western audiences.
  • In addition, the author likes using Gratuitous English using wordplay to assign significance to English words. Thanks to the author's limited grasp of the language, these often take the form of bat deductions, such as the word SIS being code for the CIA. It has something to do with sisters and systems.
• Death Note:
  • Near does this, especially in the anime, which compressed a 5 volume arc into 11 episodes. The manga explains his deductions a lot better — with huge walls of text.
  • In early episodes of the anime, L does a bit of this such as:
    • Concluding that the kills are being made by an actual human being at all, given that he lives in a world where the supernatural is supposedly impossible, it's a bit of stretch that he concludes this so quickly and with certainty.
    • Knows exactly when the first kill happened, even if a criminal dying of a heart attack right after being broadcast on TV is a weird coincidence, numerous criminals die all around the world each day, so being able to search that up and conclude which death is the first one is extremely difficult to be just glossed over in the story.
    • Figures out that Kira is a student, he thinks the times of death and kira being childish are major clues to this, for the first reason it`s not only students who are constrained by these, nor does he entertain the thought that Kira might simply be methodic. For the second reason, it's actually a pretty common thought that good criminals are dead criminals in some cultures, so you can't tell someone's age by that alone.
  • But it drops off as enough clues are established for the audience to follow what's happening. The bilinear narration between Light and L only makes it all the more obvious.
  • The light novel takes it Up to Eleven. Every murder scene involves a few absurdly complicated "clues," such as "Quarter Queen" was a child, which means her initials should be in lower case, and since she was positioned upside-down, you're supposed to flip them, therefore qq makes BB. Yeah. Half-justified by the fact that L knows that the killer is B, and Rue Ryuzaki IS the killer and is manipulating Naomi Misora into "solving" clues that he laid out, which are in fact all irrelevant, except to set up the final contest between her (and L by extension) and B. But as a meta example, that you were supposed to deduce that the guy who looks and acts very much like L was, in fact, B, who planned on killing himself, was rather out of left field.
• This is how Lucy deducted where Mavis' grave was in the exam arc of Fairy Tail. We have six hours to find the grave? The only six-letter word related to death is "demise"… and it is the only one that has the letter "E" twice… so the grave is somewhere in the E route of the first exam!
• While the story does have elements of a Fair-Play Whodunnit, the mysteries in Gosick are often solved by Victorique putting together wildly varying pieces of information, information provided secondhand more often than not and using it to put together the elaborate scenarios that make up the mystery.
• In Killer Killer, sleepyhead Bunny-Ears Lawyer detective Mekuru Katsuragi has an ability called "Drowsing Deduction", in which she goes over a case's information in her sleep and can predict the killer's location immediately after waking up.

Comic Books

• Batman:
  • Justified in Batman (Grant Morrison), where Batman points out that he needs to use half-mad logic and bizarre connective leaps to "match wits" with a rotating group of homicidal, delusional sociopaths, or people will die. Likewise, The Joker himself admits that Batman may have driven him to apophenia, as he has to constantly wonder whether or not the Bat will solve anything he plans, no matter how random everything seems.
  • During Morrison's Justice League run, Martian Manhunter shapeshifts his brain to make the irrational intuitive regions big and the logical regions small so he can think like the Joker. The chaotic maze he and Superman are trapped in suddenly appears to have a straight path from entry to exit.
  • An aversion occurs in the Batman: Endgame story arc of Batman (2011). Supporting cast member Eric Border is revealed to have been the Joker in disguise the whole time. After he reveals himself Joker explains to Batman the meaning behind the term and is actually pretty annoyed that he didn't catch onto it sooner, despite how horribly obtuse the meaning was.
  • In the Dark Nights: Metal story arc by Scott Snyder, Superman has a dream where he hears Batman saying "Carpe Diem" as they watched their sons playing the Batman TV Theme, which is related to "C.D.", a code Superman and Batman had for the most dire situations — and he thinks Batman is trying to get Superman to help him. As it turns out, the REAL code is in the song their sons play, which actually goes DC, the reverse of Batman's secret code...a warning not to come. Unfortunately Superman did, allowing the Evil Batmen to use Supes as a living battery.
  • In the short story "Who Erased the Eraser?", Batman believes that his former classmate is the Eraser based on Bat Deduction...except that he drives himself into psychological and emotional ruin because he can't make the facts fit his theory. The ending reveals that he was right that his former classmate was planning to become the Eraser, but where things went awry was that his classmate's schemes never actually got off the ground.
• Parodied in Nemesis (Mark Millar), where the title villain tries coming up with some riddles with which to taunt the police. "What's black and white and red all over?" The next day a football stadium is bombed to the ground.
• Mortadelo y Filemón: This is how "El Gang del Chicharrón" Big Bad Gedeón el Chicharrón deduces that a cat smoking is Mortadelo in disguise:
  Gedeón: Cats don't smoke. If they don't smoke, it's because they don't have money to buy cigarettes. If someone doesn't have enough to buy cigarettes it's because he is a T.I.A. agent. T.I.A. agents eat bread with mortadella. Mortadella sounds similar to Mortadelo. Therefore this cat is Mortadelo! I must get rid of it! [attempts to kick him, but hits the wall, the next panel shows a huge pile of cigarettes next to him] Brr! While I thought, he finished the pack and left.
• Parodied hilariously by Supergirl in Supergirl: Cosmic Adventures in the 8th Grade, since she thinks that her schoolmates are experts at this. She breaks a wall by accident, and cries out that "People are going to see [this hole] and know! They'll know I'm from another planet and that my cousin is secretly Superman!"
• The Disney comic Zio Paperone e l'età del ferro. Magicka and her accomplice teleport Uncle Scrooge away while he's in the middle of a family grill, pull a complex scam on him to trick him into giving them the rights to all the gold in his money bin, then completely erase his memory of what happened. Cue Uncle Scrooge somehow quickly figuring out the entire plot anyway. His only clues? He can't account for a couple of missing hours, and there's a lump of gold in his pocket.
• Parodied in an Oink! strip. When the villainous Puzzler leaves a note that says "I'm going to rob the bank in the high street. Yours sincerely, The Puzzler". Rubbishman and Boy Blunder deduce from this that water voles live in river banks, Rob is short for Robert and the highest street in the world is in Tibet: therefore The Puzzler has trained a water vole named Robert to do something unspeakable in Tibet. They spend two weeks in Tibet, but all they find is a fruit bat called Kevin. While they are away, the Puzzler robs the bank in the high street.
• In Archie Comics "Archie at Riverdale High" #33, in the story "The Outsider", a new student named Buck Bailey is repeatedly pulling nasty practical jokes on the other students, including some kids twice his size. Archie wants to help Buck (before the other kids retaliate en masse) and realizes that no one went out of their way to welcome Buck as a new student. He summarily concludes that Buck was only pulling practical jokes to get attention, and turns out to be correct, leading Archie to give Buck a more acceptable way to be popular.

Comic Strips

• In Big Nate, Nate's thinking process in response to the question "Who was Thomas Jefferson's first vice president?"
  Jefferson...Jefferson Airplane! Who made "White Rabbit"...Bugs Bunny is a rabbit. He eats carrots, which are orange. What rhymes with orange? Nothing! What's the numerical equivalent of nothing? Zero! When the temperature is zero, it's cold. What do people say when it's cold? Brr! Thomas Jefferson's first vice president was Aaron Burr!

Fan Works

• The Darker Knight takes this to an extreme.
• The Truth About Bleach has Karin deducing Ichigo might be a shinigami because she saw him in black clothes at a death memorial.
• Used and lampshaded in Twillight Sparkle's awesome adventure when Admiral Awesome arrives in Equestria.
  He opened his eyes and looked around. "Oh I'm in a land full of magical talking ponies and those ponies in tree over their fighting against the evil ponies of their evil queen." he immediately realized and thus skipped the boring introduction part so that we are right back into the action.
• In Equestria: A History Revealed, while most of the Conspiracy Theorist narrator's theories are powered by copious amounts of Insane Troll Logic, occasionally there are times when she stumbles upon something worth mentioning through these leaps in logic. Unfortunately, she usually labels them as uninteresting to note and moves on.
• In the Princess of the Blacks series, Hermione correctly deduces that Jen murdered the Dursleys. However, she reaches this conclusion from A) She knows the Dursleys abused Jen. B) The Dursleys recently died in a fire. C) She thinks Jen is an evil bitch.
• In Pony Gear Solid, this is how Snake figures out that the Patriots are controlling the events in Equestria from behind the scenes.
  The answer was in his name. Trenton. As in Trenton, New Jersey, as in the battle of. As in Washington crossing the Delaware on Christmas Eve to surprise and defeat the Hessians.
  Washington. The father of America. The quintessential patriot.
• Izuku in Deku? I think he's some pro... determines the existence of One For All because of a Master-Apprentice Chain where each member suddenly gained Super-Strength. Fair enough. But he also somehow determines that One For All stockpiles not just raw power, but also the Quirks of the previous holders, even though none of them ever manifested any of the others' Quirks. When Mirio is manifesting Blackwhip for the first time, Izuku is notably confused that the older boy didn't expect such a thing. He's later upset with All Might for not telling Mirio that One For All stockpiled Quirks, even though there was literally no reason to even suspect it could do so.

Films — Animation

• In Dumbo, Timothy the mouse and Dumbo wake up from a night of being accidentally drunk and find themselves in a tree with no memory of how they got there. Timothy deduces that due to his big ears, Dumbo must be the worlds only flying elephant. There are of course, no other possible ways of getting into a tree.

Films — Live-Action

• The Batman (2022): Mostly averted here, to show how this Batman is still a little rough around the edges. True to his usual form, the Riddler leaves behind numerous clues with his crimes, but Batman needs a lot of help to figure out what many of them mean. For example, the Riddler is very disappointed that Batman didn't manage to discover the masterstroke of his grand plan despite having left the clue to find it in his very first murder (the clue was that the murder weapon he used was a carpet-removing tool, indicating that he had hidden the plans for his masterstroke under the carpet in his apartment). Batman isn't able to figure it out until a police officer points it out to him, and by that point, it's too late.
• In Batman: The Movie, the entire universe runs on Bat-Logic, in the name of fun, though.
  • For example, at the beginning Batman gets a series of "joking" riddles that vaguely talk about birds and the sea. Batman reasons out that the riddles must be from The Riddler (fair enough), but the joking style is a sign he's working with The Joker (makes some sense). The riddles reference birds and something that "gobbles up" birds, meaning Penguin and Catwoman. Meaning the four of them are working together. And Batman is absolutely right. Even more bizarrely, the riddle that leads to the Penguin and Catwoman deduction is "What weighs six ounces, sits in a tree and is very dangerous?" which Robin deduces is "A sparrow with a machine gun!" This is the right answer.
  • Two riddles have the answers "egg" and "make applesauce". This means the villains are going to attack the UN. You see, applesauce is a single unified mixture (like the UN), and the egg is a capsule (like the UN).
  • Then there's the crown jewel of them all...
    Batman: [reading a riddle] What has yellow skin and writes?
    Robin: [holding a pencil] A ball-point banana!
    Batman: [reads the second riddle] What people are always in a hurry?
    Robin: Rushing people... Russians!
    Batman: So this means...
    Robin: Banana... Russian... I got it! Someone Russian is going to slip on a banana peel and break their neck!
    Batman: Precisely, Robin! The only possible meaning!
• Batman Forever: Upon discovering that Edward Nygma was the one sending him creepy riddles anonymously (which to the untrained eye, probably looked stalkerish but harmless), Batman instantly deduced that Nygma had actually killed a co-worker who was thought to have committed suicide. In reality, the four riddles that eventually lead Batman to deduce the Riddler's identity are, on their own, perfectly reasonable: it's the clues hidden in the riddles that defy logic, as it's not readily apparent that they're supposed to be part of a metapuzzle. Each riddle has a number in it: 13, 1, 8, and 5. These correspond to the letters M, A, H, and E. Bruce puts 1 and 8 together, making it MRE. MRE = Mr. E = Mystery. Another word for Mystery is Enigma, leading him to conclude that the Riddler is Mister E. Nygma. At least in the Peter David novelization, Bruce had to spend some time after finding the numbers trying to work out the meaning.
• The Core: Keyes manages to deduce that all the first victims had pacemakers because of the scientific specialties of himself and the other scientist brought in.
• Death Note (2017)'s version of L does this a lot because the plot of the movie is so condensed. For example, he concludes that Kira needs a name and a face to kill because he wasn't killed while giving a press conference while he was hiding his face and true name, despite the fact that up until that point Kira hadn't gone after any law enforcement. Based on the evidence he was given, L could have also concluded that Kira only targets criminals, or that Kira wasn't watching the broadcast, or that Kira didn't want to kill L on TV. In the manga and anime, L holds a press conference using a stand-in who was scheduled to be executed anyway. When Kira kills that man but not the real L, L concludes that Kira wants to kill him, but can't due to his name and face being hidden. Since this scene is so compressed in the movie, L's reasoning ceases to make sense.
• In Evolution, the scientists reason that, since arsenic is poisonous to carbon-based life forms, the nitrogen-based aliens must be poisoned by selenium. How do they reach this deduction? Because arsenic is two spaces up and one space to the right on the periodic table, so this pattern should hold true for nitrogen. They do absolutely zero testing to see if it's true before employing it live. It's also not very sound, since resistance to arsenic poisoning can be built up, and there are other elements that are more poisonous to carbon-based life... like selenium.
• In Kid Detective, this is seemingly played straight only to be subverted later with more information. One of Abe's first real cases as a child was to find the money stolen from the school fundraiser for animal rescue. He figures it must be the local rulebreaker who had once been bitten by a dog, they find the cashbox in his desk the next day and he held this victory as a badge of honor. He wasn't the real thief, as Abe was informed years later as an adult. The whole scenario was staged by the antagonist as a test of Abe's abilities and see how his mind worked, implying that they framed the other kid because Abe came to that conclusion. This was a prelude to a kidnapping of a classmate and doing so with confidence that Abe wouldn't find the right culprit.
• In Superman: The Movie, Lex Luthor somehow reasons that kryptonite is lethal to Superman just because he is from Krypton and that pieces of Krypton must have fallen to Earth just because of the location and time of Krypton's explosion in 1948 (which he knows from reading details in Superman's interview with Lois Lane, which Superman never actually provides in the interview scene — and according to the disembodied voice of Marlon Brando by the time the rocket ship carrying Superman reached Earth, thousands of Earth years passed). In addition, he somehow knows that Kryptonite strips Superman's power while slowly killing him (thereby preventing Supes from flinging it away while still under its effects). Luthor somehow knows from all this what kind of crystal to look up in his library, too. "Deductive reasoning, that's the name of the game," he says. He gets one pass in the director's cut, however. He tried EVERYTHING ELSE first, with fire, ice, lightning, etc.
• Black Dynamite brilliantly parodies the entire concept here. The logic (if you can call it that) goes like this: They are at a diner that serves waffles that melt in your mouth. M&Ms also melt in your mouth (and not in your hand) and are made by the Mars Candy Company. Mars is the Roman God of War, and his Greek counterpart is Ares. Mars backwards without the S reads "Ram", which is the symbol for Aries. Ares' half-sister is Athena, who is the namesake for Athens, Greece. Zodialogical Astronomy was invented by the Greeks in 785 BC (everyone around the table knows this). 785 is the area code of Topeka Kansas. Which can be shortened to Code Kansas. Code Kansas backwards without the last S gives A Snake Doc. A.k.a. Snake Doctor. Aesculapius is the Greek Demigod of Medicine who believed snakes' tongues had mystical healing power and whose staff surrounded by snakes is the symbol for medicine. Apollo is Aesculapius' father, and a legend involving him and snakes is in both Greek and Roman mythology — Apollo slew the serpent at Delphi. The Serpent was a big ass snake. The South American anaconda is the biggest snake in the world. Anaconda Malt Liquor has the slogan "Anaconda Malt Liquor gives you Wooooooooooo!" "Wooooooooooooo!" sounds like Little Richard. So the motto really is: "Anaconda Malt Liquor gives you Little Richard". Dick is another name for Richard. So the real motto (and the sinister plot) is that Anaconda Malt Liquor gives you a small dick. And their conclusion is immediately proven correct. Hilariously, most of the "deduction" is unnecessary to reach the conclusion, which could have been reached by itself (the shipment containers the crew found all contained Anaconda Malt Liquor).
• Subverted in The Princess Bride: Vezzini uses this to "deduce" which glass contains poison ("Iocane comes from Australia, as everyone knows, and Australia is entirely peopled with criminals, and criminals are used to having people not trust them...") Arguably, he isn't actually trying to Bat-Deduce the location of the poison — he's just trying to get a revealing reaction out of the man in black (which the man calls him on). Either that, or he's just too caught up in his own cleverness to realize that he's thinking in circles. The real irony is that all of his Bat Deductions lead to the right answer, even though he doesn't realize it: He successfully proves that he shouldn't drink from either glass.
• Subverted with Jason in Mystery Team, who sometimes makes assumptions based on the smallest pieces of evidence. Played straight later with Jason connecting the murders to Robert when he tells him to "Take a chill pill, which Robert's accomplice shouted at him to do earlier in reply to it in a phone call."
• In Without a Clue, lampshaded. A mysterious number is given, and Sherlock Holmes uses a few long and complicated leaps of logic to deduce that it means a specific theater. Specifically, the number, when taken as a chapter/verse pairing in the Book of Psalms (the kidnap victim's favorite book of the Bible), it references the name of a play that was last performed at that theater. At the end, Holmes and Watson explain to the person who left the clue how they figured it out — the victim reveals that the number was simply the address of the theater he was being held at.
• At the beginning of Journey 2 The Mysterious Island, Hank and Sean deduce the location of the eponymous island from a coded message sent by Sean's grandfather Alexander. The phrase "Son of Steve, born in 1883" leads them to Robert Louis Stevenson's Treasure Island, written in 1883, and the phrase "his last name is going fast" and the mention of the name "Lemuel" lead them to Gulliver's Travels, written by Jonathan Swift. They then piece the maps and coordinates in the three books together to form a map of the island.
• In My Big Fat Greek Wedding, Gus does this with word origins, saying all words were originated in Greek, then provides examples no matter what word he's given.
  Gus Portokalos: [when challenged on the word "kimono" being Greek in origin] Kimono... kimono... kimono... Ha! Of course! Kimono is come from the Greek word himona, is mean winter. So, what do you wear in the wintertime to stay warm? A robe. You see: robe, kimono. There you go!
• In Thomas and the Magic Railroad, Alec Baldwin does this by eating vegetables and listing off the random words that pop into his head. *eats a carrot* "Plane... drain... mountain... fountain... That might be something. I think I'll try the celery. Sausage... bicycle... *hic*... Toothpaste... Beach... Beach, that's it!" Could actually be justified here because it's a magical plant from a magical island.
• The witch/duck scene in Monty Python and the Holy Grail. The "deduction" is: Wood, ducks, and witches all float in water. Wood and witches both burn. So if a woman weighs the same as a duck, then she's made of wood, and therefore a witch.
  Witch: It's a fair cop.
• Minor example in The Blade Master: Ator mentions that his parents (whom he doesn't name, BTW) were born in a certain nearby village, and from this factoid, a pair of extras are able to deduce his identity. Again, he never specifies who his parents are. What, were only two people ever born in that village in the history of ever?
• ¡Three Amigos!. The title characters are in the desert and have no idea where El Guapo's stronghold is. They see a plane fly overhead and Lucky Day says "I'll bet it's going to El Guapo's!" He has absolutely no reason to think this, but he turns out to be absolutely right (the plane is carrying rifles to El Guapo).
• Star Wars: The Phantom Menace has Governor Sio Bibble declaring that "A communications disruption can only mean one thing: Invasion. We've lost all communications!" This before they have even confirmed that the problem is planetwide, or even that the communications disruption is the result of hostile action. While it is logical to conclude that the Trade Federation, which is already blockading the planet, would jam Naboo's communications with the rest of the galaxy (and thus their means of calling for help) prior to invading, this is hardly the only reason for a communications failure.
• Shanghai Knights. After building up Arthur Conan Doyle's deductive reasoning for most of the movie, we finally get to do some, only for it to be him going unseen from a set of facts to seemingly completely unrelated conclusions with no indication of how he got there at all.
• In The Sucker (French movie starring Bourvil and Louis de Funès better known as "Le Corniaud"), Maréchal suddenly guesses where Saroyan hid the "Youkounkoun" diamond in the Cadillac he had to drive:
  Maréchal: For sure! There are 2 Ks in "Youkounkoun", like in "klaxon"! (which is the car horn)
• In The Mask Lt. Calloway zeroes in on Stanley as the prime suspect for a bank robbery because he recognized a torn strip of fabric as part of Stanley's pajamas and reasoned that nobody else would have that bad a fashion sense. Why he reasoned that Stanley would be wearing his pajamas in a fairly popular and exclusive nightclub is anyone's guess, as is how he connected Stanley's presence at the Nightclub to a bank robbery and shootout across town.

Literature

• Deconstructed in a scene in Paul Auster's City of Glass, where it is used to show that the character doing it is completely insane.
• Joyfully subverted in Sherlock Holmes' The Adventure of the Yellow Face. The titular detective extrapolates a complex theory involving murder and foul play to explain the case to Watson without having so much as set foot in Norbury. And then, rather than every leap of logic/intuition being correct — he turns out to be ENTIRELY wrong in all his deductions — the reason the client's wife needed money and was going away at random times was that she was trying to secretly raise her child from a previous marriage.
• In Book Girl and the Famished Spirit, the Literature Club receives a mysterious letter written in a number code; Tohko immediately and incorrectly deduces the meaning based on what seems to be free-association.
  Tohko: 4 symbolizes death, so 4-5 obviously means "death finds you"...
• Early in Journey to the West, Sun Wukong's teacher decides to tell Sun Wukong to meet him at the third watch through the back door to his chambers in order to learn the secret to immortality and Kung Fu superpowers. He communicates this by smacking him three times and then leaving the room through the main door with his hands clasped behind his back. Sun Wukong figures it out, naturally.
• In The Lost Fleet, Captain Geary reasons why Syndics would delete software from evacuated base and why it looks like things have been broken into using non-standard sized tools is the existence of until now unknown and unsuspected aliens. The people he suggests this to generally state how nuts this sounds, but reluctantly admit they don't have alternate explanations. On the whole, this is a Downplayed example, as even Geary himself thinks it's an insane conclusion. He doesn't start really believing it until he starts finding other oddities that point in the same direction.
• The Department of Dead Ends in the work of Roy Vickers was described in its first appearance as an attempt to weaponize this trope. On one occasion, they caught a murderer by punning on his name.
• Dirk Gently:
  • He once came to the correct conclusion as a result of the insurance people describing an explosion as an "act of God".
    No rational cause could be found for the explosion — it was simply designated an act of god. But, thinks Dirk Gently, which God? And why? What God would be hanging around Terminal Two of Heathrow Airport trying to catch the 15.37 to Oslo.
  • In the same book he also correctly identifies one of the villains because he simply wants to blame someone other than himself for his client's death, and she's handy. He's absolutely astonished to realise, much later, that she is to blame.
• Subverted and lampshaded in Geoph Essex's Jackrabbit Messiah: Amity spends half the day desperately analyzing the notes Jack gave her before he jumped off the Roosevelt Bridge, trying maps and anagrams and numerology and other generally clever tricks to discover what message he's trying to convey. Lieutenant Springer points out that he wrote the notes to Amity, so it's unlikely that they're written with any kind of secret codes — they just have to figure out what the hastily scrawled notes refer to.
• In the Callahan's novel Lady Slings the Booze, the regulars not only manage to correctly "deduce" the existence of an extremely far-fetched terrorist plot as a thought exercise, they manage to do so just in time to interfere with it.
• In Worm, Tattletale has the ability to draw correct conclusions from a seemingly impossibly small amount of data as an actual superpower. Although she can still get things wrong if she tries to figure out too much from too little, and can get swept on divergent trains of thought if not careful.
• In The Marvellous Land of Snergs: After spending two days searching for Joe, Sylvia, and Gorbo, the King of Snergs and Vanderdecken conclude that the trio have somehow crossed over the river. It is not an implausible conclusion, but it is not clear how it was reached, since no one knew how to cross the gorge, and the trio were nowhere near it when they vanished.
• Vesta Gul, the narrator of Death in Her Hands, takes this method to an extreme. Finding a note that reads, "Her name was Magda. Nobody will ever know who killed her. It wasn’t me. Here is her dead body," she responds by making up names and characteristics of people involved, before she talks to anyone. Something of a Deconstructed Trope in that she doesn't solve anything this way.

Live-Action TV

• The 1966-68 Batman series made liberal use of this, as the various villains would usually leave clues for the World's Greatest Detective, and the correct solution almost always required Bat Deductions. This turned up pretty often with The Riddler.
  • Once, Batman solved one of the Riddler's riddles that wasn't even spoken or written. Riddler used a wax-based solvent to dissolve a hole through the wall of a vault, and on doing a forensic investigation of the crime scene, Batman's chemical analysis revealed it to contain Nitrogen, Uranium, and Sodium:
    Robin: If you take the first three letters of those elements, it spells N-U-S...but that doesn't mean anything.
    Batman: Reverse the order, and what do you have?
    Robin: S-U-N.
    Batman: Of course, that's got to be it!
    Robin: But what's it supposed to mean?
    Batman: Robin, I'm surprised at you. You're supposed to be studying French in school. What's the French word for sun?
    Robin: Soleil!
    Batman: Correct. The Riddler has left us a clear indication of where he intends to strike next. Back at Madame Soleil's wax museum!
  • The series was so aware that it was going to rely on this sort of thing that invoking the trope formed the backbone of the plot of the very third episode. The Penguin, being out of ideas for a heist, sends a random umbrella to Batman. His plan: Batman will analyze the "clue", use Bat Deduction to figure out what the Penguin is planning, and the Penguin will hear it through the radio transmitter hidden in the umbrella, and then go and commit that crime! A brilliant inversion, lampshading, and subversion all in one.
  • Batgirl once deduced the plot of an episode based on the fact that her father was late getting home and that a new singer was in town. The episode was meant to be connected to the previous one, where she had met the villain and guesses her cover is that of the singer.
• Agent Mulder from The X-Files often solved the case of the week out of the blue, though there were instances of him being wrong in his assumptions or cases where his (or Agent Scully's) logical steps were shown. One of the true non-paranormal detective episodes, "The Amazing Maleeni" about the magician who seems to decapitate himself for real during his act left all the clues in a breadcrumb trail and a sufficiently sharp viewer can deduce the conclusion and unravel the entire mystery just before Mulder gives the solution in the final reveal.
• Star Trek: The Original Series:
  • This exchange from "The Omega Glory" about two warring factions, the Yangs and the Kohms:
    Kirk: Yangs? Yanks? Spock, Yankees!
    Spock: Kohms? Communists? The parallel is almost too close, Captain. It would mean they fought the war your Earth avoided, and in this case, the Asiatics won and took over this planet.
  • In "Return of the Archons", where based solely on the fact that society is very bland and monotonous, Kirk becomes certain that the mysterious lawgiver named Landru must be a computer that is programmed to control the entire planet, which indeed turns out to be the case.
• In a season seven episode of Star Trek: Deep Space Nine, Ezri, while trying to solve a murder case, deduces that the killer is a Vulcan who lost all his friends based on the fact that each of the murder victims had pictures of their friends and family laughing in their quarters. She's right, but that's quite a logical leap.
• An episode from the last season of Charmed opened with Billie deducting that, to search for her sister who was abducted by demons, she needed to find a powerful bloc that demons would work with. Simple — corporate America. And since she's read this story about a guy who was kidnapped as a child and now works with "corporate America," she's going to try a magic spell to see if he has anything to do with demons. And this works.
• The Colbert Report:
  • Stephen Colbert used this technique to twice pick the Oscar winners. He has a shockingly good success rate.
  • Colbert parodied himself by using the technique to "pick" the winner of the 2008 Presidential election. He kept using starting points clearly designed to point to John McCain but wound up picking Barack Obama every time. Even when he started on... John McCain. Video
  • Colbert and others generally use this kind of reasoning in parodies of Glenn Beck's chalkboard illustrations.
• In one episode of Criminal Minds Reid correctly figures out who the murderer is by hypothesizing the murderer had multiple personality disorder, based on a single anomaly in a polygraph test because the suspect got a control question wrong. Instead of concluding the subject failed math, he went through the conclusion that on that one question a second personality took over (a phenomenon they had no evidence for) knew the answer to the question, lied about it (even though it had no incentive to do so on the first question), and that lying on the test meant that the suspect was indeed the murderer. To be fair, Reid had already clued in that something was wrong: his first hint was the uncharacteristic behavior the suspect had after the test.
• In Season 2 of The Flight Attendant Megan is stunned when Cassie finds her in the bar in Reykjavik she's been hiding in. Cassie explains she saw through the code of emojis Megan was sending her, the Cherry in it meaning the bar in Iceland they once visited and her message of "bring the lockbox key to the Queen of Long Island" meant Megan needed it. A disbelieving Megan tells her that the message was for Cassie to bring the key to their friend Cherri, who works at the Queens strip club in Iceland. Both women are amazed Cassie was able to track down Megan's hiding space off this message.
• In The Secrets of Isis, Andrea (Isis's alter ego) has her car stolen when she visits the library. In the spot where her car was parked, she finds a rag, which she takes back to her lab to have it analyzed and decides it has enamel laquer on it, which means that her car isn't being shipped out of the state to be sold, rather it's being kept in California to be repainted. Next, she says all the car thieves in a car ring had been busted except for one guy who got away, so it must be him, then determines her car must be at this person's salvage yard. When she gets there, there's a sign on the door that says it's out of business, but there's an old chain on the gate with a new lock, which could only mean one thing: the car thieves are operating out of this salvage yard!
• Parodied in an episode of 30 Rock: Tracy finds a food voucher that expires at midnight, but finds it impossible to eat that much food. The personification of leap day suggests that he goes back to "where he came from". Tracy's thought process is: We all came from the sea, C is a letter of the alphabet, alphabet soup, soup kitchen, kitchen, the Kitchen Debate with Nixon, Richard M Nixon, the M-Train, Soul Train, Chicken Soup for the Soul, chicken soup, soup, soup kitchen. All while standing next to a mobile soup kitchen.
• In an episode of Bones, Brennan deduces that the murder weapon must be The Slaughter's Chalice, a famous goblet that's been lost for centuries. She discovers this because there's traces of precious stones on the body. What makes it especially bad is that the traces contain diamond dust, which even she admits is not part of the chalice, meaning she cherry-picked which evidence to include in this deduction. Brennan, who won't speculate that sharp force trauma to the sternum indicates murder. The only thing that lends the slightest amount of credence to her idea is the fact that one of the suspects is known to be a collector of ancient artifacts, but the chalice wasn't even brought up before this point.
• In the Irish drama series The Big Bow Wow, a drug dealer is in a record store when he hears an employee direct someone to the blues section for Miles Davis. But the dealer knows Miles Davis belongs in jazz ... so the employee must be an impostor ... and since the dealer himself is a wanted criminal, obviously this person is an undercover cop and the store's being used in an elaborate sting! He's right and initiates a shoot-out with several victims.
• Cassandra Cillian in The Librarians 2014 uses a mix of math, science, hallucinations, and free association to see hidden patterns.
• Ray Velcoro in True Detective season 2 puts together who the killers of Caspere are and that they have the missing hard drive...based on a picture of them as children and having briefly met them in passing as adults months earlier.
• Parodied (like everything else) in the Angie Tribeca episode "Ferret Royale" — detective Geils goes from "apple" to "orchard" to "farm" to "granny smith" to "Grandma" to "nursing home" to "soft food" to "applesauce"... and then back to apples, starting the loop over again and repeating it two or three more times.
• That Mitchell and Webb Look: According to the "History of Numberwang" sketch, Professor Betrand Russell discovered the theory of Numberwang one morning after staring at a jug for a moment. From there, he managed to deduce how one could determine what is or is not Numberwang. Then he smashed the jug to prevent anyone from copying him.
• Late Night with Jimmy Fallon does this (or at least a parody of this) when they do a random word association that couldn't possibly make much sense if you didn't arrive at that conclusion beforehand.
• Elementary: Subverted when Sherlock is assessing the cause of death for one Body of the Week:
  Sherlock: Venom, no doubt. This time delivered straight from the fangs of a deadly coastal taipan.
  Watson: How can you tell?
  Sherlock: There's one right behind your foot.
• Probe's "Computer Logic": Austin deduces a number of things about Mickey that he fails to provide his reasoning behind, such as how he knows about her allergy to chocolate, or how he knew her mother had surgery recently. The most reasonable deduction he makes is that she's broke and needs a job.
• Some of House's deductions are quite a reach. In "Pilot," the patient of the week turns out to have tapeworms in her brain, which House figures out because she has ham in her fridge. He doesn't test the ham in any way; he just thinks ham = pork = tapeworms and turns out to be right. And he calls Foreman an idiot because he hadn't mentioned the ham, thinking it irrelevant.
• Robyn Hood (2023):
  • Robyn figures out that an alleged social worker is really an undercover cop because "her people don't turn on each other", aka a black person shouldn't be supporting the police. She also determines that a rabbit costume she found in a random locker means that said woman is the "monster" who tortured Tuck, even though there was no mention of a rabbit by anyone nor did she know said locker belonged to that woman.
  • Marian determines that John Prince has a far bigger and more sinister plot than simply buying Sherwood Towers and evicting the residents based on the fact that he, a land developer, owns a lot of land in the city. While she's correct, it's literally his job to own land.

Radio

• Occasionally used in The Goon Show as a form of Insane Troll Logic:
  "Let's see, it's 1956 AD... A and D are the first and fourth letters of the alphabet. One Four... One for the road? There are many roads. Such as Cecil Rhodes. He lives in Africa... that's it! I'll search for the missing year in Africa!"

Riddles

• You are trapped in a locked, windowless cell with only a chair, a piano, and a baseball and a baseball bat. What are the three ways you can get out?
  • Break the chair in two, and put the two halves together. Two halves make a whole. Crawl through the hole and escape.
  • The door is locked. Pianos have keys. Keys unlock doors. Take one of the piano's keys out of the piano and use it to unlock the locked door.
  • When someone fails to hit a baseball with a baseball bat, they get a strike. Three strikes and you're out.

Tabletop Games

• The Mutants & Masterminds expansion book "Mecha and Manga" introduced the Conspiracy Theorist feat which lets players make Knowledge rolls on completely unrelated (and untrained) knowledge skills after rolling a 20 (or less with further ranks) on their previous skill roll. A series of successive high rolls quickly produces Bat Deductions as your character moves from Knowledge (Technology) to Knowledge (Civics) to Knowledge (Natural Sciences) to note that not only are devices in question mind control devices, but that the particular composition of police officers means the president must be on a secret visit, and that the peculiar white coarse hair caught on the boxes means that there's a diabolical plan by Dr. Silverhair, the transfigured ape turned Nazi, to kidnap the president.
• In Vampire: The Masquerade there's Dementation, the Malkavian exclusive discipline. The third rank allows one to "Gain insight into the nature of something through seemingly random patterns". This effectively allowed players to jump to horrifically far-fetched conclusions on the basis of very scant evidence. (In-universe, explainable by Malkavians having an unusual and limited kind of Hive Mind possessing all the information to draw these conclusions from either logical deduction or direct precognition... but as every Malkavian is incurably insane — in individual ways — none of that gets through in recognizable form.)
• Tabletop Role Playing Games in general will have characters doing this, since their players will, intentionally or not, inevitably combine in-game knowledge with meta-knowledge. Such meta-knowledge includes assumptions that challenges will be reasonable for the characters, knowledge of obscure monsters, general knowledge about tropes and cliches, and most importantly, understanding what sorts of plots the person running the game is likely to run.
  • In tabletop role-playing games where characters have statistics representing intelligence or knowledge of specific subjects, characters can solve moon logic puzzles for the players. If the player Jamal is stuck interpreting half-missing fragments of a coded message in a dead language, but his character Archeos the Magnificent has an intelligence score of 32 out of a maximum possible 18, the Dungeon Master may provide a hint.

Video Games

• 64th Street: A Detective Story: Rick, an expert detective, somehow managed to deduce the kidnappers' hideout by reading through various job ads packaged with the criminals' ransom note, spelling it out to his amazed protégé Allen. It... Makes Just as Much Sense in Context.
  Rick: Read these job classifieds very carefully. Notice the similarities between the sentences in the ads and the sentences we saw in the letters from the kidnappers last night?
  Allen: Holy sh...eboygan. Really?
• Inverted in Touch Detective 3. Inspector Daria and Mackenize are stumped as to why someone has been going around stealing nothing but bananas. Daria "reasons" that the only kind of person who would steal people's bananas is someone who doesn't respect banana lovers, and as a sentient being made out of bananas would, by definition, be a banana lover, the thief's objective is absolutely NOT to make a sentient Banana-Man out of their stolen bananas. This is absolutely the thief's objective.
• Heavy Rain: While Norman is playing a video of a fight between himself and the Origami Killer from earlier in the game he notices that the killer has a golden watch, therefore he is or was a cop because the station always gives that model for promotions. In fairness, he's desperate, grasping at straws, and it's still not enough information to find the real killer. In fact, if you think that's the final clue, then you'll accuse the wrong person (the local Rabid Cop). You have to cross-reference that with all the other clues you've gained to narrow things down to one person.
• L.A. Noire:
  • Cole deduces that from the corpse of a recently stabbed victim he finds a ticket, therefore the fighter you were looking for is in the theater. Even your Partner lampshades this as ludicrous.
  • Cole deduces that a car crash victim was raped the day prior to getting involved in the car crash because ripped panties were found in the handbag that was in the car. Although this isn't the most illogical leap in the world to make for a detective, mere minutes later when he's questioning the car's driver, Cole whips the underwear out as proof that the driver is hiding the passenger's rape because the driver didn't mention the fact that the passenger was raped when they were giving a basic description of who she was. To be fair she does make an expression that makes it obvious she's hiding something about the passenger, but it's still an incredibly bizarre leap of logic. And this is made worse by the fact that the game expects the player to be on the same boat as Cole without any prompting whatsoever. Despite the game not even remotely implying it, the player needs to have the theory of rape on hand by the interrogation, and needs to make the incredibly bizarre leap to accuse the driver of lying and then present the underwear to the driver when they describe the passenger without mentioning the fact that she was raped. Due to this, this interrogation question is one of the infuriatingly non-intuitive in the game and trips up close to 100% of all first-time players by official Rockstar Social Club statistics.
• In Sam and Max Save the World: "Bright Side of the Moon", Sam figures out Roy G. Biv's identity through a long chain of reasoning that has nothing to do with the actual clue in his name (a mnemonic for the colours of the rainbow).
  Max: We're detectives, Sam, not mind-readers! Maybe we should ask Hugh Bliss.
  Sam: Mind readers! That's it! ... No, that's not it.
  Max By the way, have you seen my copy of "Emetics" the handbook for multi-coloured happiness by Hugh Bliss?
  Sam: Colours! ... No. Think, Max, think!
  Max: I know I had it this morning.
  Sam: That's it! "Morning"! In the ancient tongue of the mud-worshipping Kappalahotek tribe of the Serengeti, our word "morning" means "he who destroys the hypnotic rainbow man"! That's the word he fears the most! So this Roy G. Biv is the one person we've met who's never said the word "morning"! That means it's—
  (phone rings, Sam answers)
  Sam: It's the Commissioner!
  Max: The Commissioner? I never did trust him!
  Sam: No, chucklehead, it's Hugh Bliss!
  Max: Never!
• Towards the end of Yakuza 0, both Kiryu and Majima both receive coded messages from the Amon Clan telling them to meet at a specific place. While Kiryu translates the message easily enough, Majima gets the code confused with baseball terminology and instead reads the message as "Just nine pitches. Come to the pitching place. Amore." Despite this mix-up, he reasons that 'pitching place' must mean a 'bullpen' and that 'Amore' is an Italian word and Italian is kinda similar to Spanish before putting 'bullpen' and 'Spanish' together to suss out the correct meeting place, a bullfighting arena, anyway.
• In Disco Elysium, the Inland Empire skill (the Shout-Out to the David Lynch film of the same name is very deliberate) essentially allows the Player Character do to this. Well, sometimes. Quite a few times it just makes him see supernatural events, vast conspiracies, and vast conspiracies involving supernatural events where there are none, but there are also many times where the far-out deductions that the skill allows the player to make is actually on the money. For instance, you can tie one character correctly to a piece of evidence because it contains racism, they made a bigoted remark, and "that's not something a good person would say". They confess immediately.

Visual Novels

• Umineko: When They Cry: This is how Battler figures out Beato's game and becomes the new Game Master. One of the clues that Battler used was Knox's 6th: It is forbidden for the case to be resolved using accident or intuition, so Bat Deduction should easily be averted by the readers.

Web Animation

• In the first season finale of Rooster Teeth short films, Matt leads Joel through a massive Bat Deduction that ties together all of the previous episodes with rather tenuous connections. One example is that the truck that hit him in "Catch" was made in Detroit, which has a high rat population, which is controlled through rat poison, which was put in their coffee in another episode... the end of this train of thought is the box/time machine from the first episode.
• In Red vs. Blue: Revelation, Sarge uses this from a radio conversation with Simmons to figure out that Wash and the Meta have taken Simmons and Doc hostage, and killed Donut and Lopez. The sequence starts out with Simmons leaving several good clues and Sarge being surprisingly clever with genuine deductive reasoning, but quickly devolves into this trope, as Grif looks on bemusedly. By the time we get to see Simmons again, it's not even clear whether he was leaving clues or, as he suggests, he couldn't say anything with Wash and the Meta listening and Sarge simply put it all together through his own insane brand of logic.
• In Episode 4 of the Simgm Productions Pretty Little Liars spoof Spencer deducing Meet from Chicken being a Meat and Abandoned Warehouse from "one" because Rosewood only has one.
• Water-Human at one point has one of the characters learn that Water-Human is in a city, which is somehow enough of a clue for them to instantly deduce the entire plot so far, point by point, despite being absent since episode one. "Of course, I might be wrong..."

Web Comics

• Happens in Freefall, when Helix uses this to find Sam.
  Helix: With so many people here, I figured you must be hiding. You're good at hiding, so I knew you'd pick a spot I'd never think of. So I took a map of the spaceport and filled in every place I could think of. Then I went to the spot that wasn't filled in and here you are.
  Sam: Helix, why is it every time you think, it's my head that hurts?
• Deconstructed humorously in this episode of The Non-Adventures of Wonderella. The Quizzicle believes the note reading "Find me" in the Pond's Paraffin Foot Bath will be sufficient to make Wonderella think of someone who has a pond and a "pair of fins." She'll then go snooping around Doctor Shark's pond and fall into The Quizzicle's trap. She short-circuits it by not realizing she's meant to be making a deduction at all, and The Quizzicle and his mooks wait so long to spring their trap that they die there.
• The Axe Cop and The Adventures of Dr. McNinja crossover "Stolen Pizza, Stolen Lives" has a weird example that's either an actual Bat Deduction or a relatively reasonable inference (given the crazy world of Axe Cop) that's made to sound like a Bat Deduction by the way it's explained.
  Axe Cop: Look at this goo.
  Dr. McNinja: It's going into that manhole cover.
  Axe Cop: That's a monster door. Only monsters can go in there. There are secret monsters in there. They must be stealing the pizzas.
  Dr. McNinja: What?! How do you know that?
  Axe Cop: I'm the smartest man in the world.
  Dr. McNinja: Oh.
• This kind of logic is mocked ruthlessly in this strip of Full Frontal Nerdity where Frank is trying to get the guys to play a puzzle-based RPG called "Escape the Room", which is modeled off films such as "The Cube" and "Saw". They proceed to complain about Frank's puzzle logic being so weird that not even the Adam West era Riddler would use it.
• In xkcd:
  • Beret Guy is a total Cloudcuckoolander in his deductions... but that doesn't mean he's not right. In "Cursed Chair", he's accidentally bought a cursed chair from a mysterious shop, and when he tries to return it, the shop has been boarded up. The other guy remarks that most shops are closed due to the coronavirus. This leads Beret Guy to infer the chair must have caused the pandemic, and he can stop the pandemic if he destroys the chair. He appears to be right. Certainly the floating evil office chair says nothing to deny it.
  • Further, in "Puzzles", Randall complains about and parodies the prevalence of this in children's adventures:
    Kid 1: Aunt Gertrude must have left a clue to the amulet's location.
    Kid 2: Hmm. Wait a minute. Gertrude. G.
    Kid 1: As in "Ground!"
    Kid 2: And "diG a hole!"
    Kid 3: I'll get a shovel!
    Kid 4: To the yard!
    

Web Videos

• In the LoadingReadyRun Rapidfire Comedy Sketches, they intermittently show a police detective (or, in later episodes, two bouncing ideas off one another) following this sort of train of thought, eventually proven right by way of a much simpler solution.
  Riley: Today's Friday, Coroner puts TOD about 12 hours ago, that makes it Thursday, or Thor's Day, Thor being the Norse god of Thunder. Thunder and lightning are formed when two weather systems of opposing charges come together. Charge begins with C, Weather Systems with a W. C and W, the initials of Cyrus Walker, local playboy and socialite who runs a thriving pork futures firm and was recently indicted for corporate fraud. The journalist who broke the story was Janet Smith, local reporter and wife, I think you'll find, of your suspect, Ted Smith, 375 Carinhood Road.
  Rodriguez: That's pretty much about it, he turned himself in this morning.
  Riley: Outstanding.
• Morgan Freeman uses this in Celebrity Bric-a-Brac Theater to determine who killed Dennis Hopper and how. "Bees... Cos-Bees! It's obvious!"
• The theory in this Pachelbel rant about Pachelbel's first name: "It's probably Johann. They were all named Johann." It's a parody of Insane Troll Logic, the joke being that it's correct.
• CollegeHumor have a sketch where '60s Batman uses Bat Logic to twist every riddle into being about the local pub.
• In one Game Grumps sketch, Danny manages to figure out that the Santa that's currently wrecking the studio is actually a bird because...everyone keeps using bird metaphors for no discernible reason.
• Joueur du Grenier:
  • In the test of The Legend of Zelda: Faces of Evil, this is how JdG finds the solution to unlock a door after listening to a really obscure hint in a dialog. He then says that it was a joke: he was stuck there and was forced to read a walkthrough.
  • The Trope Namer itself is featured in the review of Batman: The Movie, causing a serious breakdown.
  • Ironically, JdG (or rather, Duck-Man) makes one such deduction himself in the DC Comics games episode. Since the least awful of the games tested by Seb was Aquaman, then Joker-Seb must be hiding... under the sea.
• Parodied in JoJo's Bizarre Adventure Abridged, where Joseph, through an insane series of jumps ends up with a false deduction. Fortunately, Dio doesn't know he's barking up the wrong tree and ends up spilling the beans before Joseph can lay his bizarre theory on him. The leap he makes from there makes no sense either: He deduces that Dio's Stand has the power to breathe fire.
  Joseph: Nrg! I don't have time for this. Wait, Time. Chronos was the god of time in Greek mythology. Greece won the Euro Cup in 2004. George Bush was re-elected in 2004. George Bush was impersonated in Harold & Kumar Escape from Guantanamo Bay. Kal Penn is a part of Barack Obama's administration. Will Smith looks like Barack Obama. Will Smith's son's going the be in the next The Karate Kid... Oh my god I've got it!
• Also parodied in Yu Yu Hakusho Abridged, where Kurama tries to pick out the correct door through the use of math and pop culture. Kuwabara picks out the right door, but through the heavy spirit energy concentrations coming from behind it. Kurama is not amused.
  Kurama: Let's see... there are 15 doors, 4 Saint Beasts, 3 planes of existence, and 1 castle. The sum of these numbers is 23. The Number 23 is a movie starring Jim Carrey, and has a score of 8% on rottentomatoes.com. The most popular brand of tomato ketchup is Heinz No. 57. 57 divided by 23 is approximately two and a half. Two and a Half Men is a sitcom starring Charlie Sheen. Therefore—
  Kuwabara: [facing correct door] It's this one.
  Kurama: ...Well, yes, that is the only logical path, but how could you have known?
  [later]
  Kurama: If you do or say one more thing to annoy me in the next 24 hours, I swear to Koenma I will cut you in half with a fucking rose! Or do I need to remind you I have that capability?
• TheRealJims's video "Who REALLY Shot Mr. Burns? (Part 1)" discusses The Simpsons two-part episode "Who Shot Mr. Burns?" and how well the solution that Maggie shot Mr. Burns works, arguing that the weakness with the solution is its dependence on symbolism, saying "Symbolism is not evidence, it's just a writing device. You cannot go to your local police station and explain because it was raining during a recent murder, that the murderer must be the man selling umbrellas. They will look at you funny, and probably arrest you.". He would subsequently make more videos proposing alternate solutions that either Marge, Lisa, Bart, Grampa, and Homer shot Mr. Burns, instead, which would still tie into the foreshadowing from Part 1 and the show's canon.
• Solid jj's "Death Note but they order fast food" culminates with both Light and L making the same far-fetched chain of inferences about what Misa really meant by what she said... even though she didn't.
  Misa: "Can we get Taco Bell instead?"
  Light and L: "Taco Bell?"
  L: Taco Bell? Why on Earth would she suggest Taco Bell? Is this part of your game, Kira?
  Light: Wait. Taco Bell was founded in 1962. That was the same year that Marilyn Monroe died.
  L: Marilyn Monroe had 13 letters in her name. Her name makes two words, making up 15. Her third film came out in March 15th. "Beware the Ides of March."
  Light: The Romans praised their own god of death. "Mors." The god of death and casualty. "Casualty" in Spanish is "Baja". The Baja Blast! I get it! She's trying to say she'll kill him! Right here and now!
  L: So that's your game.
  Light: Yes, do it, Misa. Tell L you want a Baja Blast and secure my position as the god of the new world!
  L: You're going to make a move right here, right now? Do your worst, Kira.
  Misa: "Wait, can you even get a Bic Mac at Taco Bell?"

Web Original

• When Bikes Argue 2 has the following exchange:
  Hilo: Here's the battle map!
  Ackro: All I see, are, grease smudges!
  Hilo: The one close to me looks like an alien spaceship! Because the Martians have agreed with us that the ghost town's gotta go! ...
  And the mushroom cloud-like [grease smudge] next to you... is the end of Muhammy al-Dracula!
  Ackro: And where are we gonna get plutonium to nuke Mecca from, a DeLorean???
  Hilo: Snagnabbit, that's it! If we can't find plutonium for the bomb, we'll never convince the werewolves to come out during a crescent moon!
  Because they'll be showing Yogi Bear reruns if that happens!!! This completely ruins the whole plan!
  ::Hence, Hilo realizes that Ackro is right in saying that it's preposterous for bicycles in a pole barn to nuke Mecca. But his reasoning doubles as both Right for the Wrong Reasons and Bat Deduction!
• The creator of that film, in a blog post, writes a Deconstructive Parody of a popular Call It Karma poem that could also count as Bat Deduction or Insane Troll Logic:
  When the bird is alive, PETA makes propaganda out of it.
  When the bird is dead, Monty Python makes comedy out of it.
  But that's neither here nor there when discussing whether or not there is a time to kill or a time to heal. You ain't gonna out-Solomon Solomon that easily.
  But if you gotta bust somebody up, choose your targets wisely. Sometimes, they bring their friends in low places.
  A tree may make a few thousand matchsticks; but that won't mean jack if your house gets flooded.
  So...it is better to have everyone think you're crazy, but have a backup plan for everything; than to have no one question your sanity when a 747 really does nosedive right into your living room.
• Seanbaby, on Batman and the Riddler (in the animated Super Friends cartoon):
  For example, people like you can see an oven and grunt out loud, "oven is hot. Hot things hurt. Hurt is bad. It is bad to touch oven." The Super Friends see an oven and shout, "oven... heat... lava... Great Gotham! The Legion of Doom's headquarters is in the heart of a volcano! Let's roll!" But the most insane part is that they're usually right.
• The Editing Room:
  • They did a parody screenplay of Angels & Demons, in which Robert Langdon (referred to in the script as Tom Hanks) does this really often.
    Tom Hanks: Let's see here... we're in a tomb. Tomb... like Tombstone pizza, which is circular. Circular is the opposite of square... of course! To Saint Peter's Square!
  • And then when Vittoria (referred to as Ayelet Zurer), who has been wondering why the hell this is working, attempts the same thing:
    Ayelet Zurer: Wait let me try one. Okay, so this guy was chained up... chains are often used for construction work... the fourth cardinal is at a construction site!
    Tom Hanks: What? Don't be stupid. The fourth element is water, so he's in a fountain.
    Ayelet Zurer: Goddammit.

Western Animation

• Parodied, and ultimately subverted, in Amphibia. Anne and Marcy are sent a puzzle-gram by King Andrias, and Marcy solves the first two clues all by herself, making Anne feel inadequate by comparison. Her attempt to "fake it 'til you make it" and solve the third and final clue (which has Marcy stumped) consists of a baffling chain of logic that leads her to deduce that the final part of the message is in the sewers. Not only is Anne completely wrong, but she almost gets the entire party eaten by a giant Sewer Gator in the process.
• In the Justice League episode "Legends", the Justice Guild of America, a team of heroes from a Silver Age Retro Universe, gets notice that the bad guys are planning a crime spree themed for the four classical elements. The Guild members immediately figure out what these refer to, even if they are only tangentially related to the elements themselves: The fire crime is the theft of the famed fire ruby (a gem), the air crime is the theft of an "antique flyer", the water crime is the theft of a new fountain being dedicated by the city's mayor, and the earth crime (this one is a doozy, and the biggest Bat Deduction of all) is the theft of the trophy for the clay court tennis championships. The League is pretty confused by this development, to be fair, which is one part of The Reveal that neither the Guild nor its enemies are real.
• South Park:
  • A Running Gag in the episode "Cancelled", a parody of Independence Day, the scientist (Jeff, for Jeff Goldblum) would fixate on a random element that has nothing to do with the problem whatsoever and follow a completely nonsensical chain of reasoning, eventually arriving at the correct solution. For example:
    Jeff: Wait a minute: buttsex!
    Chef: [confused] Buttsex?
    Jeff: Buttsex requires a lot of lubrication, right? Lubrication. Lubruh... Chupuh... Chupacabra's the, the goat killer of Mexican folklore. Folklore is stories from the past that are often fictionalized. Fictionalized to heighten drama. Drama students! Students at colleges usually have bicycles! Bi, bian, binary. It's binary code!
    Chef: [still confused] ...Who's having buttsex?
    
    Jeff: There's a huge ship of some kind in Earth's orbit! But why? Wait a minute: chaos theory! Chaos theory, it was first thought of in The '60s. Sixty. That's the number of episodes they made of Punky Brewster before it was cancelled.^note Incidentally, he's off by twelve, making the success of this deduction even more baffling. Cancelled... Don't you see? The show is over! The aliens are cancelling Earth!
    
    Jeff: Whoever they are, if they're receiving messages, they might be sending them, too. Wait a minute: candy bars. They usually come in a wrapper. Just like you... wrap a Christmas present. Christmas happens when it's cold. Cold, as in Alaska — that's... with polar bears. Polar bears... pola... polarity! I can switch the polarity to see what transmissions are coming from the location this one is being sent to!
    Chef: THAT DOESN'T MAKE ANY GOD-DAMNED SENSE!!
  • Also parodied in the episode "Mystery of the Urinal Deuce", where Cartman claims to deduce that Kyle caused 9/11:
    Cartman: Two minus one is one; one one - 11; two minus one is one; one one, and there are nine members on Silverstein's board of directors. That's nine-one-one. Nine-eleven. And take 2 - 1 + 9/11 and you get 12, which leads us all to the mastermind of the 9/11 attacks: Kyle!"
• Played with in an episode of Teenage Mutant Ninja Turtles when Donatello finds the bad guys by doing a long, drawn-out series of calculations... then looks up and sees all the fireworks.
• Johnny Bravo is prone to doing this; one episode even features Adam West, who exhibits this kind of logic by interpreting a fortune cookie that said "Your heart's afire" to mean the Johnny's Momma was being held hostage at a golf course. And then he interprets the flag sticking out of the holes as signs of a race of mole men who are plotting to create mole-human hybrids so they can Take Over the World.
• Professor Farnsworth of Futurama uses this a lot in "The Duh-Vinci Code":
  Professor Farnsworth: Animatronio mentioned a fountain. That's a statue of Neptune, god of water. The number of points on his trident is three, or "tre". The "u" in his name is written like "v". "Tre", "V". "Tre"... Trevi! It's the Trevi Fountain! There can be no question!
  Leela: But, Professor—
  Professor Farnsworth: THERE CAN BE NO QUESTION!

Even better is the fact that he ignores the more obvious deduction, the Fountain of Neptune, also in Rome.

• Naturally, episodes of Batman: The Animated Series involving the Riddler had this sometimes:
  • "What is Reality?" begins with three computers crashing around Gotham, displaying only a riddle on screen: "Where does a 500-pound gorilla sleep?"^note Anywhere it wants to. "What's worse than a millipede with flat feet?"^note A giraffe with a sore throat. "How do you fit 5 elephants into a compact car?"^note Two in the front, two in the back, and one in the trunk. Train of logic: the Riddler doesn't usually use such commonly known riddles meaning the answers to the riddles are a red herring. The riddles themselves all contain numbers: 500, 1000, 5. Convert to roman numerals and get D,M,V... the Department of Motor Vehicles!!!
  • After escaping a trap from Riddler, the latter calls Batman on a payphone and says "Ask me no questions and I'll tell you no tales. It all makes sense when you add it up." followed by a handful of coins falling in the change tray:
    Batman: Penny...Penny...Cent...Red cent...Copper! It's made of copper!
    Alfred: And "copper" is another word for "policeman"!
    Batman: And no tails means heads. Police...Head...Quarters!
    [...]
    Batman: Four quarters and one penny equal 101 cents, so... Police headquarters, room 101!

  The silliest thing about this? Batman was going to go back there eventually anyway.

  • Finally, at the end of the episode, Riddler casually remarks "If the planet were equitable, I'd still have my old job" right before his virtual reality program crashes trapping him inside. Batman immediately deduces that to be a clue to his hideout: "If the WORLD'S FAIR, I'd still have my EX-POSITION". Robin is not amused.
• Underdog. Apparently, "A rhyme/In time/Saves nine" means "Underdog should come to the town's diamond store to stop a heist." Ah, yes. "Time... like Big Ben... Ben's Jewelry Store!"
• On the Black Dynamite animated series, in a Call-Back to the movie, the characters use the following chain of logic to figure out the episode's real plot: there's Jello and grits on Black Dynamite's plate. Jello is jiggly. It's jiggly because it contains collagen. Collagen is also found in marshmallows. Marshmallows are used to make s'mores. The only thing blacker than a s'more is a black panther. The other kind of panther is The Pink Panther. The Pink Panther theme goes "da-dant, da-dant, da-dant," which sounds like "dead ant." Ants live in colonies. Another word for a colony is a clan. "Clan" is a common term for the Ku Klux Klan. So the murders are being committed by an alliance between the Black Panthers and the Ku Klux Klan. They only get one fact wrong; it was a splinter group called the Black Pumas (they couldn't get the trademark) instead.
• On Tom Terrific, Manfred will say something off the cuff that will lead Tom to this. In "Go West, Young Manfred," the two are in the old west trying to find a way to deliver gold to the survivor of the trek to California:
  Manfred: Please, Tom. Don't saddle me with your problems.
  Tom: Saddle. Pony. Pony express!
• Danger Mouse does this in "The Wild Wild Goose Chase" as he and Penfold are about to get devoured by an alligator.
  Penfold: 'Cor, and I thought this (tongue) was a bloomin' carpet.
  DM: That's it, Penfold. Carpet, wool. Wool, sheep. Sheep wolf. Wolf, pack. Pack, case. Case, trunk. Trunk, elephant! [DM does a Tarzan yell, bringing in a herd of elephants, on which he and Penfold catch a lift]
• Miraculous Ladybug:
  • "Sapotis": In the original French dub, Ladybug gets a teapot as her Lucky Charm and somehow deduces that she has to go to Master Fu for assistance when Chat Noir makes a comment about being too young to drink tea. In the English dub, Chat Noir's line is changed to a comment about his kung-fu getting rusty, making Ladybug's deduction more plausible and thus averting this trope.
  • "Passion": Played with. Mister Bug's Lucky Charm is a perfume bottle, which he connects to Gabriel Agreste's house based on a perfume advertisement that lands right next to him. Lady Noire thinks it's a reach, but he asks her to trust him, since she has often drawn similar conclusions from seemingly flimsy evidence. In reality, he has already deduced where the akuma is, and the Lucky Charm was just a pretense to hide where he got that knowledge.
• The Fairly OddParents!: When Timmy temporarily lends Cosmo and Wanda to Tootie so she can have the birthday of her dreams, Crocker manages to correctly guess what happened... because Tootie's cake is made with real buttercream icing.
  Crocker: NOBODY MAKES THIS FROM SCRATCH ANYMORE!!!

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