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Innocuously Important Episode

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An episode that seems to have no importance to the main Story Arc. After a major revelation later, the episode turned out to be much greater with significance in retrospect.

May use a Chekhov's Gun and related tools, but telegraphing is avoided. Compare with Arc Welding where a Story Arc is created retrospectively from isolated episodes.

Some examples of Jumping the Shark and Franchise Original Sin demonstrate the negative aspect of this trope (minus creators' intention) in which an episode or gimmick that at first appears silly but harmless turns out to be an indicator of future problems with the work.

The examples, naturally, contain Major Spoilers.


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    Anime and Manga 
  • Cowboy Bebop has the episode Sympathy for the Devil. The first time through the episode might seem to be just another episodic romp, abet one with an immortal creepy kid. However, the episode not only hints at Spike's cyborg eye, but it also has a lot of parallels with the finale, from a villain who Spike's Not So Different from to Faye wishing Spike off as he's about to go on a presumably fatal mission, to Spike ending the episode pointing his finger like a gun and saying "Bang".
  • Detective Conan: The anime adaptation of Detective Conan took a lot of freedoms from the very beginning. This turned out to be problematic when a seemingly unimportant case from early on (which had been adapted in the episode "Mystery Mastermind" and altered so one minor character does not die) turned out to be very important: The minor character was Ai Haibara's sister and her death triggered her sister's Heel–Face Turn. Ai then becomes a main character, one of the few people that know Shinichi's secret and the only one in the same situation. When the manga reached this point in the story the anime had to create a filler - "The Black Organization: 1 Billion Yen Robbery Case" - that told the exact same story with the same names and everything of "Mystery Mastermind", only with Ai's sister dying. Hence, a lot of confusion.
  • Dragon Ball:
    • In the early portion of the Red Ribbon Army arc, Goku meets a robot/cyborg named Android 8, who briefly helps him out in Muscle Tower. Many years later, we would meet Android 8's creator, who sets into motion the entire Android/Cell arc and the major events that happen because of it.
    • During the 23rd Tenkaichi Budokai arc, Piccolo and Kami speak to each other in a language nobody but they understand. In one of the few pieces of intentional foreshadowing, said language is written in a distinctly sci-fi alien font, hinting at the later revelation that they're Namekians.
  • Fullmetal Alchemist loves doing this. The only even slightly minor character who has only one appearance was the terrorist from the fourth chapter. Even he shows up again. Both Bald (and Colonel Genz from the video game) appear in an advertisement for automail in chapter seventeen.
    • In the 2003 anime version, you didn't think Russell and Fletcher would be content helping Bellsio with his farm for the rest of the show, did you? It seems Russell enjoys borrowing Ed's identity a bit too much. Too bad the second time he does it, the homunculi have Ed pegged as an enemy after the events of Lior. Also there's Rose.
    • The Brotherhood anime has an original story for its first episode, showing the characters chasing and fighting a rogue State Alchemist called Isaac, who is on an anti-government rampage because he doesn't trust the Amestrian higher-ups. He fails as you would expect a filler villain would. In fact, you would be forgiven if you thought this episode is pure filler to introduce newcomers to the series. However, it is full of Foreshadowing: everything Isaac says about the Amestrian government is spot-on, it introduces several characters (like Kimblee) dozens of episodes before they become relevant to the plot, and even his grand plan to freeze the city with alchemy (by creating a city-wide transmutation circle made up of smaller circles) foreshadows the climax of the entire series!
  • The heartbreaking episode Affection in Ghost in the Shell: Stand Alone Complex is seemingly an episode made to highlight some of The Major's tragic backstory. Turns out it also tells Kuze's backstory too, and explains how he and The Major met when they were much younger. This does not become explicitly apparent until the final episode of the series, and doesn't become apparent to Motoko herself until right before the final scene of that episode.
  • Gungrave: The first episode of the anime might seem like just another mindless shoot-'em-up, but in the second episode you suddenly get to the real story, which is a mob drama.
  • In the Haruhi Suzumiya light novels, Endless Eight was exactly this. This short story gave the motivation for the whole fourth book, which most people didn't pick up on. So Kyoto Animation went all out and made EIGHT episodes out of it, setting up the Disappearance movie.
  • Madlax pulled this off with its Beach Episode, of all things, wherein Vanessa discovers that her employer is in cahoots with Enfant and eventually follows the clues all the way to Gazth-Sonika, unwittingly facilitating the meeting of the series' main protagonists, Margaret and Madlax.
  • Episode 3 of Magical Girl Lyrical Nanoha seems like a standard Monster of the Week plot (especially because the series abandons that format with the introduction of Fate the following episode), but it's probably one of the most important episodes in the entire franchise. It established Nanoha's habit of pushing herself to the point of exhaustion (something that would come back to bite her hard), showed the beginning of her signature fighting style, and saw the creation of the Area Search spell.
  • After Caldina does a Heel–Face Turn in Magic Knight Rayearth, she tells Fuu that at least the Magic Knights have a goal- as compared to Zagato, whose reason for this hullabaloo is unknown. Until then, the three girls had genuinely thought that Zagato was simply out to take over Cephiro. Nothing else is mentioned about this for now, and the Magic Knights continue their mission. This is one of the first hints that there will be a Wham Episode coming up.
  • In Naruto, the 'Kakashi Gaiden' arc was, for the longest time, just considered to be some interesting Filler that covered some of the backstory of Kakashi and explained where he got his Sharingan eye and somewhat "eccentric" mannerisms, put in between the pre- and post-timeskip stories as a sort of Breather Episode. With The Reveal that Tobi is really Uchiha Obito, who we saw die in that arc it becomes apparent that it was actually the introduction and backstory for one of the series' two joint-Big Bads!
  • While One Piece author Eiichiro Oda is a past master of the Chekhov's Gun, one instance that hits this trope is the Skypeia arc. A largely standalone arc with no immediate connection to the primary story except for the near-end reveal that Gold Roger had been there himself. At least four very important things derive from this arc, however:
    1. The treasure obtained in this arc is used to purchase the materials for the Straw Hats' new ship, the Thousand Sunny.
    2. During Skypeia we see several characters with a Combat Clairvoyance power called "Mantra." Five arcs later, at Amazon Lily, we get implications that Mantra is, in fact, the first overt in-story use of a power known as Haki. Some time after that it's outright confirmed that Mantra is the name by which Skypeians know the "Color of Observation" form of Haki. After a Time Skip, several of the Straw Hats learn to use it.
    3. Skypeia introduces and is the source of Dials, a Bamboo Technology that main character Usopp then adopts and uses extensively until Usopp acquires Pop Greens seeds, as well as spawning a technological revolution that provides easier oceanic transportation and even a music industry that another main character Brook becomes a part of.
    4. In Eneru's cover story, the reader is shown that he and the other winged people of Skypeia and Shandia had ancestors on the Moon and left extremely advanced technology there, including a robot army, so advanced that it's coveted by pirates from other planets. His cover story ends with Eneru and his robots readying up to return back to Earth, indicating a larger importance not only to Eneru, but also connects the winged people of the series to the Moon and to the ancient history the World Government tries to suppress at all costs.
    • The battle between Ace and Blackbeard at the tail end of the Enies Lobby Arc. The events and repercussions of the battle set up the single biggest conflict of the first half of the series later on.
    • The episode during the Albasta Saga when Ace parts ways with the Straw Hats, giving Luffy a piece of paper. For a good long while, it appears to be nothing more than an ordinary piece of paper, until at the end of the Thriller Bark Arc, Lola gives one to Nami, explains that this is a special type of paper called a Vivre Card, and Luffy realizes it's just like his. He later sees that the card is beginning to burn and shrink, indicating Ace's life force is waning. But since Ace doesn't like people to fight his battles for him, and the burning down can reverse if the person is stronger, Luffy writes it off. Which is a HUGE mistake in the long run when he learns Ace has been sold out by Blackbeard and sent to Impel Down.
    • Ace also mentions seeking out Blackbeard, a traitor to Whitebeard's crew who killed one of his crewmates. Drum Island Arc makes a passing mention to him and four other crewmates going on a rampage there, causing Wapol to lose his kingdom. In the Jaya Arc, there are several unusual people in Mock Town who could be confused for the local colors and general riff-raff. Then Luffy meets a complete stranger who shares similar ideals to his, and outwardly seems like a pretty likable guy, becoming a friendly acquaintance of Luffy's. Until he suddenly decks Sarkies of the Bellamy Pirates without breaking a sweat and tries (unsuccessfully) to claim Straw Hat's bounty for himself. Turns out he's Blackbeard, and is a backstabbing two-faced fiend, and those people from Mock Town are part of his crew, while another is off lobbying to get him a seat among the Seven Warlords. Nobody outside of Whitebeard's crew knows who he is since he's a relative upstart among pirates, but after Ace tracks him down and they finally fight, following the aftermath of the battle, everyone knows who Blackbeard is. By Impel Down/Marineford Arc, Luffy learns the truth about him, and it packs a wallop.
    • The Baratie arc near the beginning of the series shows that Sanji had grown up in the North Blue and ran away from his family to the East Blue. Over 700 chapters of the manga later, we find out who this family actually is: The notorious Vinsmoke Family, a nuclear family made of Mad Scientists and Gadgeteer Geniuses who took over the entire North Blue in the past and gained enough influence for the World Government to recognize them as nobility. They had finally tracked Sanji down and stuck him into an Arranged Marriage so the Vinsmokes can gain further power in the New World through one of its emperors.
  • Pokémon:
    • The Diamond and Pearl episode "Noodles Roamin' Off", Meowth finds out his Fury Swipes give him culinary ability. This seemingly just builds to a one off story where he becomes a noodle chef, only to quit by the end of the episode. However Meowth would continue developing and using this talent in several of Jessie's coordinator events later on.
    • Another Diamond and Pearl episode "The Thief That Keeps On Thieving!" reveals that Jessie and James' careers as Team Rocket's agents have dwindled so badly that Giovanni has forgotten who they are. This ends up coming into play at the end of the Diamond and Pearl series, since Giovanni forgetting their previous failures leads to them being offered the Unova promotion.
  • Episode 33 of Revolutionary Girl Utena is one of the several recap episodes. While Utena's recap episodes tend to have some significance, such as explaining (some of) the weirdness behind Nanami's fillers, this episode contains Utena's loss of her virginity to Akio, the event that sets in motion the Apocalypse arc that makes up the final 6 episodes of the series.
  • Steins;Gate: The first episode introduces the characters and setting, and begins to get into the concepts of time-travel used throughout the series, but the events of that episode also turn out to have far more significance than they'd seem. Okarin's time-travelling efforts in the final episodes show the events of that day as they truly unfolded, and towards the end of the last episode Okarin watches his past self discover Kurisu seemingly dead, remarking that he was to begin the most important 3 weeks of his life.
  • Str.A.In.: Strategic Armored Infantry: The fanservice episode redeems itself by setting up a major plot point that, later on, leads to many a Heroic B.S.O.D., the outing of Sara's identity, the cementing of the True Companions, and the death of one unexpected major character.
  • Tengen Toppa Gurren Lagann: Episode Five seemed like a fairly basic Released to Elsewhere plot made in order to add to the adventuring party, but the themes in that episode proceed to permeate the entire third quarter with glorious darkness.
  • Episode seven of Tokyo Magnitude 8.0 seems like a perfectly positive enough filler episode depicting how Mirai has grown and the beginning of a Sick Arc for Yuuki. That is until the last moment when Yuuki collapses. In the next episode he is brought to a hospital but subcumbs to his cranial injuries.
  • Chapters 9 and 10 of the Yu-Gi-Oh! manga, where Yugi duels Kaiba for the first time. What at first appears to be a simple Monster of the Week plot leads, directly or indirectly, to every following story arc, the two anime's greater focus on the card game, and the anime spinoffs.
  • Toei's Yu-Gi-Oh! (first anime series) has episode 19. While the overall plot is unrelated to the overarching story, Ryou Bakura appears, causing Yugi to wonder about himself and his other self, and Mokuba cameos at the end to signal preparation for the Death-T arc.

    Comic Books 
  • The 9th issue of Grant Morrison's run on Action Comics, sandwiched between "Superman Versus Brainiac, Fuck Yeah" and "Superman Versus Captain Comet (While Batman Chuckles At His Secret Identity Problems)" was an interlude involving parallel universes, a Corrupt Corporate Executive who creates a machine of incredible power allowing a monster to enter his world, and a black version of Superman who is the president of his America. The monster, Superdoom, comes to fight the main universe Superman in issues 17 and 18. It also turns out that the machine's creation is the result of events in The Multiversity.
  • The 1991 DC Crossover Armageddon 2001 had a bunch of tie-ins that occurred in that summer's annuals. Most of the annuals had standalone stories that had no effect on their main books, but the Superman annual for that year ended up foreshadowing key events in the Super-books, such as Superman deciding to finally take down Intergang once and for all which happened later that year, and Superman leading the rest of the DC heroes against against Brainiac's invasion of Earth in the "Panic in the Sky" storyarc which happened a year later.
  • Justice League of America #166-168 from the 1970s features the League swapping bodies with the Secret Society of Super-Villains. No real significance at the time, but the 2000s mini-series Identity Crisis revealed that this incident led the League to start wiping villains' memories (including Doctor Light, whose personality change significantly altered the character), and brought about severe distrust issues among the members of the League which culminated in the group's downfall.
  • Grant Morrison's Seven Soldiers of Victory series consists of seven miniseries that all initially seem to be telling different stories, but ultimately overlap. Also, the Leviathan, a monster made up of hundreds of feral kids that appears in one issue of the Klarion mini-series, later turns up in Batman Incorporated as a sinister organization.
  • The Spider-Man arc "I Killed Tomorrow" is a fast-paced, fun beat-the-clock arc rife with humour and energy. The two-issue arc deals with Grady Scraps' invention of a Time Door that allows for travel to and from the future, and neatly wraps itself up at the end. It plays like a "breather arc" in the period between the intensity of Spider-Island and the epic sprawl of Ends Of The Earth. Flash forward to the Superior Spider-Man arc "Necessary Evil", and it turns out this Time Door is the passage through which Miguel O'Hara, Spider-Man 2099, comes to the present day and is subsequently stranded here.
  • In Transmetropolitan, Spider Jerusalem goes looking at the Reservations! Warren Ellis gets to write social science fiction! Too bad Spider gets exposed to the substance that leads to his debilitating brain condition...

    Fan Fiction 
  • The New Adventures of Invader Zim:
    • Episode 5 seems like just another case of "Dib tries to find an edge on Zim and suffers Epic Fail" like so many in canon. However, his actions cause the senior Swollen Eyeball agents to decide in the following episode to assign Steve and Viera to help him, thus significantly changing the status quo.
    • Episode 8 is just filler about Viera and Gaz coming to blows (ultimately literally) due to clashing personalities. But Gaz maintains a serious grudge over this, to the point that come Episode 19 she uses a phone number Norlock left her (also in Episode 8) to tell him and Zim where to find Project Domination just for a shot at payback.

    Films - Live Action 
  • While Ant-Man and the Wasp is for the most part a self-contained palate cleanser after the events of Avengers: Infinity War, this movie has been stated as "the most connected" to Infinity War's sequel. The implication is that the Quantum Realm and all the exhausting explanations of it might factor into that movie's story.
    • This is emphasized in the mid credits scene, which shows the entire Pym family turning to ash due to Thanos' finger snap and Scott becoming stranded in the Quantum Realm.
  • Avengers: Age of Ultron may seem like a Villain of the Week episode involving the titular bad guy at first, but the events of the film have serious repercussions for the MCU, to the point of having a ripple effect. The casualties resulting from the fight in Sokovia, as well as other places where the Avengers fought, eventually leads to the Sokovia Accords being established and the Avengers splitting up, and the main antagonist of Captain America: Civil War is motivated by revenge for having lost his family in the battle at the end of Ultron. By the time Infinity War starts, the heroes are still divided, making it all the more easy for Thanos to win. Even in more self-contained films like Spider-Man: Homecoming and Ant-Man and the Wasp, and television shows like Agents Of Shield, the Accords have an impact.

  • Bridge of Birds: Every seeming Wacky Wayside Tribe turns out to be this by the end.
  • In the Dirk Gently series, Dirk's "holistic" philosophy isn't wrong in the context of the books — even the aside jokes are relevant later on.
  • The Dresden Files:
    • Book three, Grave Peril, has serious implications reaching all the way out until Changes. (And likely beyond, as books continue to be released. Word of God says that all the guests at that little party will be seen again.)
    • Going back to the first book, Storm Front, the ritual used by Victor Sells is the same one the Red Court wants to aim at Harry in Changes, the twelfth book.
  • Harry Potter:
    • Harry Potter and the Chamber of Secrets set up Harry Potter and the Half-Blood Prince seven years in advance. It set up the concepts of Horcruxes through Riddle's diary, it introduced the four Hogwarts founders and established Voldemort's connection to the Slytherin bloodline, the basilisk fang from the Chamber would later be used to destroy two of the Horcruxes, and the idea that Voldemort inadvertently passed some of his abilities to Harry would prove to be major foreshadowing for the revelation that Harry was an accidental Horcrux. It introduced Ron's sister Ginny (who would become Harry's primary love interest by Half-Blood Prince), and the concept of "blood purity" and Pureblood supremacy would become major lynchpins of the mythos by the end. And in one scene, Nearly Headless Nick convinces Peeves to destroy a cabinet to distract Filch for Harry; the broken cabinet becomes a major plot point in Half-Blood Prince. Not bad for a work that at first glance looks like a book-long Wacky Wayside Tribe.
    • Harry Potter and the Philosopher's Stone seems to be a relatively light introduction to the Wizarding World that ends with all of its loose plot threads tied up. Upon rereading it, though, one realizes how important it really is to establishing the core themes at the heart of the series. The Big Bad fails to kill Harry because of the Magical protection granted by his mother's sacrifice, Nicholas Flamel chooses to die from old age to prevent anyone else from using the Philosopher's Stone for evil, and Voldemort's plan turns out to revolve around getting his hands on the substance that can make him immortal. The theme of death—Voldemort's fear of it, and the heroes' willingness to face it—plays a major role. In later books, it becomes clear that it's also the Central Theme of the series as a whole, and we gradually find out that all of Voldemort's actions are driven by his quest to cheat Death and become immortal. Dumbledore's speech at the end ("To the well-organized mind, death is but the next great adventure,") is a poignant moment, but it takes several more books before we realize how important it really is.
    • Harry Potter and the Philosopher's Stone also has several chapters that seem to be completely irrelevant to the main story. If a chapter is not important to something that happens later in the book, it foreshadows something that happens in one of the later books.
  • The Hitchhiker's Guide to the Galaxy sets up a few of them, mostly in the first book. A person is mentioned in the prologue and then dismissed with "but this is not her story"; the same prologue is used in the fourth book, only now it is her story (as well as Arthur's). Then there's Arthur's first encounter with Vogons, in which he says that he wished he had a daughter so he could forbid her to marry one. Four books later, he does have a daughter, and she's quite rebellious—though she and the sympathetic Vogon character introduced in the sixth book never actually meet. Finally, there's that bit about the bowl of petunias thinking "Oh no, not again", and the book says that if we knew why it was thinking that, we might know a lot more about the universe than we do now. We find out the answer in the third book. Notably, Douglas Adams was making it up as he went along, and would deliberately leave threads like these dangling with no idea of what, if anything, he was going to do with them. So when he did tie up a loose end, it was as much a surprise to him as to the rest of us. Another example is the implication from Arthur's encounter with Agrajag in Life, The Universe and Everything that Arthur cannot die until he's been to Stavromula Beta, which doesn't even seem to occur to Adams until two books later, when he has to construct a kind of Shaggy Dog Story (and an incredibly lame pun) to wrap up a loose end he hadn't even acknowledged previously.
  • The "Riddles in the Dark" chapter of The Hobbit is revealed to have been surprisingly significant when the reader starts with The Lord of the Rings, partly because Tolkien had to change it to fit the new book's continuity.
  • The prologue to A Game of Thrones is like this to the entire A Song of Ice and Fire series. The prologue to A Feast for Crows serves the same function within that book, setting up plot that doesn't truly get put into motion until the last chapter, some 900 pages later.
  • The Warrior Cats novel Dark River is one of these. At first it seems to be an interesting romp based on forbidden love, but looking back on it with Omen of the Stars completed and Dawn of the Clans coming soon it's one of the most important books in the series. It introduces the Ancients (the shared root of the Tribe and the Clans), Rock (who is revealed in The Last Hope as the cat who gave StarClan the prophecies), Dark Forest cats entering the real world, and the Tunnels (a massive Chekhov's Location).

    Live-Action TV 
  • Babylon 5. Several episodes of the first season.
    • The thirteenth episode "Signs and Portents". The episode's "A" plot is some fairly standard and unimportant thing involving Raiders [space pirates] and a Centauri artifact called The Eye. The "B" plot, involving the first appearance of the enigmatic Mr Morden and the question "What do you want?", turns out to be incredibly important and crucial to the rest of the series — but the episode's retrospective importance only kicks in at the first season finale.

      Its importance was lampshaded by the fact that the entire first season was also named "Signs and Portents" (though a casual viewer wouldn't know this - the season titles only appeared on fan sites.) "Portents", of course, are hints about future events.

      The A Plot does have one rather important thing happen in it: it's the first appearance of The Shadows. They even get name dropped, but in a way that most viewers would dismiss as unimportant on a first viewing.
    • "Midnight on the Firing Line" is the former Trope Namer. The first episode after the pilot movie, it featured subplots and character moments that the show kept referring to throughout many of its best moments over the rest of its run.
    • "Infection", the fourth episode of the show, managed to introduce several elements that would become very important later on, including Interplanetary Expeditions, ISN, Earth's desire for advanced biotechnology and the first mention of previous Shadow War a thousand years ago - and certain revelations about Sinclair's past and how it drives his behaviour in the present. Not bad for what is almost universally considered to be a lackluster Monster of the Week episode.
  • The Battlestar Galactica first-season episode "Tigh Me Up, Tigh Me Down" was thought to be a comedy filler episode (the only intentionally comic episode in the entire show) revolving around a series of misunderstandings between Ellen Tigh (who unexpectedly reappears in the fleet) and Commander Adama (who believes Ellen is a Cylon sleeper agent). The whole episode climaxes in an amusing scene where everyone humorously works out their differences, and the matter is resolved. Three seasons later, in "Sometimes A Great Notion", it turns out this episode set up the eventual arc and reveal that Ellen was the final Cylon.
  • Buffy the Vampire Slayer.
    • "Killed By Death" (and earlier, "Ted") seemed a bit out of place at the time of airing (robots? really?) but set up the suspension of disbelief needed for the Buffybot to exist in that series, which allowed Dawn to stay in Sunnydale after the events of "The Gift". Also, this episode introduced Warren, who would become a major villain in the following season.
    • "Killed By Death". Buffy is sick and ends up in hospital - a place she hates since her cousin died in a hospital when they were children. While the Monster of the Week in the episode (which was also responsible for her cousin's death) is dealt with, Sunnydale General ends up playing a big role in Season Five - not only does Buffy's mother Joyce end up with a brain tumor and spends a few episodes there, but we're also, at the same time, introduced to the character Ben Wilkinson, a young medical intern who serves as a possible Love Interest to Buffy and who turns out to be the mortal, human shell of Glory, the Big Bad of Season Five - Glory's plans, in turn, result in Buffy's death in the Season Five finale.
  • Community foreshadowed Chang's rise to power at Greendale in several earlier season 3 episodes, including "Contemporary Impressionists".
  • Doctor Who:
    • "The Daleks" was initially written as a space adventure story based on 1950s sci-fi serials, with anti-war themes and some quirky Nazi-like "bug-eyed monsters" as villains. Due to the extreme popularity of aforementioned villains, it is now impossible to watch the story without being aware that this is the Doctor's first encounter with the Daleks.
    • "The Tenth Planet" has three main points about it that get very important later. It introduced the "Base under Siege" formula that would dominate Troughton's tenure and influence the show's slide from a Genre Roulette format into Monster of the Week, introduced the Cybermen (though they were given a soft-reboot a few episodes later), and ended with a shock twist of the Doctor suddenly turning into a totally different actor. All of these at the time were just decisions being made for that particular episode and Real Life Writes the Plot, but due to Who's Kudzu Plot nature all became very significant (although some in terms of the show's feel rather than in plot points).
    • "The Web of Fear". Intended at the time as a sequel to an earlier story about the Doctor teaming up with the military and a now-older ally to fight killer robot Yeti in the London Underground. The impact is massive - here is where the Brigadier gets introduced (in fact, he's the prime suspect for being the Great Intelligence's vessel for most of the episode, something that would not have been done had they known he would be a regular), here is the start of the UNIT arc and here is the start of the "Yeti on the loo in Tooting Bec"-style horror that would form the Pertwee era of the show.
    • The first episode of Season 6, Episode 1 of "The Dominators", introduces us to Cully, an ageing Manchild from an alien species with two hearts, whose disgruntlement with his people makes him crave adventure and go travelling in his ship with a bunch of awkward teenagers. He lands and his entire crew gets murdered. This is an innocuous opening for a filler story at the time, but takes on a new meaning when you compare it to the last episode of Season 6, Episode 10 of "The War Games", in which the Doctor is confirmed to be a Time Lord on the run from his boring civilisation and his crew get sent back to where they were from by the other Time Lords (including the implicit death of Jamie).
    • "The Brain of Morbius" was intended as a Filler Bottle Episode, but several of the Doctor's throwaway lines in the story imply that the Time Lords aren't as godlike and advanced as they had previously been portrayed. This could easily be brushed off by the fact that the Doctor hates the Time Lords and (in that incarnation at least) has an unreliable grasp on reality, but Robert Holmes picked up on it and used it as Foreshadowing for his Wham Episode, "The Deadly Assassin", which revealed the Time Lords were a bunch of stagnant old politicians with Chronic Backstabbing Disorder.
    • "Silver Nemesis" had Cybermen vs Neo-Nazis, but it set up the "Wolves of Fenric" arc with Ace and the Doctor as Chess Master motif which concluded in rather sinister style in "The Curse of Fenric".
    • "The Unquiet Dead", which introduces the Rift in Cardiff. Without that rift, the events in "Boom Town", the show's first, third and fourth series' finales and "The End of Time" would not have taken place... nor any of Torchwood.
    • "The Long Game" sets up a lot of later events — including the Ninth Doctor's regeneration — as the Doctor's actions lead to "Bad Wolf". Meaning of course that it also has perhaps the most relevant title of the entire show.
    • "The Christmas Invasion" appears to be nothing but a Christmas Episode to establish the newly regenerated Tenth Doctor but it actually set up many events for the next seasons. There's the first appearance of the Torchwood Institute, the santa robots come back during Donna's first appearance, the Doctor deposing Harriet Jones, Prime Ministernote  ultimately results in Harold Saxon taking her place and last but not least, the Doctor's severed hand is later retrieved by Jack Harkness and become important to both this series and the spinoff Torchwood.
    • The ending of "The Shakespeare Code" includes William Shakespeare using words to stop the villains. The last episode in the season, "Last of the Time Lords", took that concept and turned it Up to Eleven. The relationship between the tenth Doctor and Elizabeth I is later explored in the 50th anniversary special.
    • In series 3 of the new series, "The Lazarus Experiment" set up both Martha's family's betrayal to Harold Saxon/The Master, and the aging device was used against the Doctor in the season finale.
    • Similarly, "Human Nature" and "The Family of Blood" appeared to be an updated retelling of a tie-in novel, leading to a unique circumstance where fans familiar with the spinoff media were actually less likely to realize these episodes were this trope, which comes off as exceptional filler otherwise. In fact, they set up the Master's return.
    • "The Lodger" seems like a filler episode (albeit a fun one), but we later learn that the black TARDIS belongs to the Silence, the Big Bad of the next season. Craig returns that series for a single episode, where it turns out he's the source of the TARDIS-blue envelopes from the beginning of the season.
  • Farscape:
    • "A Bug's Life" has a story about Peacekeepers and a virus capable of possessing people, but the repercussions of that episode would echo throughout the series and beyond.
    • "Beware of Dog" had a fairly ridiculous main plot, with a B plot of Crichton going crazy and imagining Scorpius around every corner — but it's a brilliant setup of the entire plotline for the rest of the season, one that would continue throughout much of the series.
    • The very first time Crichton hallucinated Scorpius was in "Crackers Don't Matter", a nutty, off-the-wall episode where everyone's going crazy and fighting over crackers.
    • "A Human Reaction", a well done though not especially memorable episode - until it's revealed a few episodes later that the major plot point of the entire series was set up during its events.
    • "Won't Get Fooled Again" seems like just another one of the series' frequent visits to Bizarroworld, but the ending reveals the existence of the neural chip in Crichton's head and its accompanying mental clone of Scorpius, both of which are crucial to the Myth Arc.
    • "Eat Me" is just another Monster of the Week episode, and just another episode where Crichton gets split into duplicates (yes, it happened more than once). Then at the end it turns out that the duplication of Crichton was permanent. Cue most of the rest of the season being split between two groups of characters on separate ships, each with its own Crichton.
  • Fringe's Bizarro Episode, "Brown Betty" (2x19) at first appears to be funny Breather Episode after some important revelations in the previous four episodes. Walter tells Olivia's niece Ella a drug-addled musical noir-style detective story using all the regular cast members... then gives the story an incredibly dark and bitter ending about how only one man can have a mechanical heart and one must die without it. The ending reflects Walter's guilt about stealing Peter and irrevocably damaging the alternate universe and how he feels the only good he's ever accomplished has come at the price of destroying children's lives (i.e., the cortexiphan trials). It reflects the major theme of the next season, that only one universe can survive; one must be destroyed, leading to the Bad Future glimpsed in the Season 3 finale, "The Day We Died". However, Ella rejects Walter's unhappy ending and creates an ending where the heart can be shared, symbolizing Peter realizing after seeing the Bad Future there is another option: he can bridge the two universes, which will heal them both. Peter even does this with the aid of a grown-up version of Ella Dunham, bringing it full circle back to "Brown Betty".
  • In the second season of GARO called Makai Senki, there is a flashback episode, in which the childhood of the main character Kouga is seen. The episode seems rather unimportant, until the final episode reveals Kouga knew the Big Bad as a child, who made Kouga promise to kill him if he ever turns evil.
  • How I Met Your Mother:
    • At first glance the "Showdown" episode seems like pure filler with Marshall and Lily preparing for their wedding and Barney going on The Price is Right. However, we learn two episodes later that Ted and Robin broke up at this time. It also sets up Barney's story arc of searching for his father that dominates most of season 6.
    • One episode features a jokey subplot in which Marshall is unable to have sexual fantasies about women other than Lily without first imaging an intricate scenario in which Lily dies of an unspecified disease and gives him her blessing to move on once she is dead. The widely-reviled ending of the show featured something similar, with the Mother dying of an unknown illness and Ted's children enthusiastically giving him the blessing to go after Aunt Robin years after the fact. Given that this ending was filmed between the first and second seasons, it's highly likely that the Marshall-Lily plot was completely intentional foreshadowing.
  • Lost had a lot of these.
    • Sometimes the writers themselves didn't realize how important an episode would be until later, as was the case with Season 2's "One of Them", which introduced Henry Gale a.k.a Ben Linus, originally intended as a recurring character who would die after a few episodes, but who went on to become the Big Bad for the next season and a half, and who remained crucial to the show's mythology even after completing a Heel–Face Turn later on.
    • Season 1's "House of the Rising Sun" appeared to be a standalone episode mostly intended to fill in the back story of Jin and Sun at first. Its B-plot included the discovery of two skeletons that weren't even mentioned after that point until season 6, but which turned out to be major figures in the island's history.
  • The Mad Men third season episode "My Old Kentucky Home." On its face, the Four Lines, All Waiting story serves as a series of character vignettes bound by the "work disguised as fun" theme. However, this episode introduces us characters that become prominent in later episodes (Connie Hilton, Henry Francis); and story arcs that carry through the next couple of seasons (Peggy's introduction to the counterculture, Joan realizing that marrying her doctor is not going to give her the life she thought she wanted, Betty looking for a way out of her marriage, among others).
  • Merlin had three:
    • In the first series "The Gates of Avalon" was a fairly basic Monster of the Week story, in which Arthur is targeted by two murderous Sidhe, but it also introduces the fact that Morgana is a seer which marks out her entire Character Arc from then on.
    • Series 2 has "The Lady of The Lake" introduce Freya, Merlin's love interest who dies at the end of the episode, but becomes The Lady of The Lake and helps Merlin retrieve Excalibur in the series 3 finale.
    • The third series had "Queen of Hearts", which seemed a one-off filler which once more returned to status quo by the end of the episode, but it also introduced the character of "Dragoon", Merlin's old-man disguise which he puts to even greater effect in series four.
  • Monk has its first Christmas Episode, which is a standard case of the week with a scene that reveals that Monk is still keeping the last gift his late wife left him wrapped up. It's set up as yet another moment showcasing Monk's undying love for her. Four years later however the Grand Finale reveals that said gift contains the evidence that reveals who the mastermind of her murder is.
  • Power Rangers
    • Power Rangers Operation Overdrive's "One Fine Day" was a lighthearted episode featuring the Rangers on a camping trip which gets interrupted when their enemies erect a forcefield to search for part of the season's MacGuffin. A alien-powered human chain used as an attempt to pass through the forcefield is a major clue that that the Red Ranger isn't human when it breaks, foreshadowing his Robotic Reveal character arc a few episodes later and his death-seeking Heroic Sacrifice in the finale.
    • Power Rangers RPM's "Tenaya 7" not only properly introduces the titular cyborg villainess but also before she blows her cover, a throwaway line about a metal detector getting "false positives" gains new meaning when in the two-part finale Big Bad activates the sleeper drones among half of Corinth's populace including the officer who says said line.
    • Mighty Morphin' Power Rangers season 3's "Master Vile and the Metallic Armor" introduces the Zeo Crystal which not only serves to reverse the time shift in the Alien Rangers arc, but also its later attempted theft causes the Command Center's bombing and later serves as the basis of next season's powers.
    • And than Zeo mentions its Big Bad's ties to an "alliance of evil" which is later prophised in the Millennium Message of Power Rangers Turbo, then abducts mentor Zordon and plays a big role the Zordon Era's Grand Finale Power Rangers in Space.
  • The Pushing Daisies episode "Circus Circus". No other episode sets up as many of the major arcs and themes in the second season: the corrosive effect of secrets; something new beginning as necessarily implying something else ending; stasis as the opposite of life/death/rebirth; the impossibility of simply picking up a relationship where it was left off; one's persona or public self versus one's True Self; a parent's inability to recognize his or her child.
  • A season 2 episode of Sliders introduces the Kromaggs as mere monsters of the week but they become the main antagonists in the last two seasons.
  • Stargate Atlantis: In the first season, they encounter a planet that had been developing a drug that would make them immune to the Wraith feeding on them, but also has a 50% chance of killing the person injected. It seems like a one-off story, until the middle of season 4 when their enemy, a Wraith-turned-human-turned-hybrid gets hold of the drug and begins to spread it across the galaxy. It plays an important role in several episodes from then to the end of the series.
  • Star Trek: The Original Series:
    • "Balance of Terror" and "Errand of Mercy" introduce the Romulans and Klingons, each of whom goes from Villain of the Week to major galactic power throughout the rest of the franchise.
    • The episode "Space Seed" seems at first like another example of episodic 60's-era TV—a bad guy named Khan tries to take over the Enterprise, Kirk outwits him and exiles him and his followers to an uninhabited planet, life goes on. Then Khan returns, and the ensuing events greatly influence the rest of the TOS-era movies and set up some plot points for the TNG-era series, Star Trek: Enterprise, and the reboot movies.
  • Star Trek: The Next Generation:
  • Star Trek: Deep Space Nine:
    • An early random Ferengi comedy episode "Rules of Acquisition" reveals that something called "the Dominion" is a major power in the Gamma Quadrant. The war against the Dominion is the Myth Arc of the show.
    • Season 5's "Rapture" was a heavy Bajor episode, focusing on the planet's future and Sisko's role as Emissary. The main thrust of the plot is Sisko gaining visions of the future, which are slowly killing him. Before Bashir operates to remove this ability, one vision was of locusts hovering over Bajor before moving onto Cardassia. A later two-parter saw the Dominion enter the Alpha Quadrant and set up shop in its newest member, Cardassia. The same two-parter also revealed that Bashir had been replaced by a Changeling by this time, offering a new reasoning for "Bashir" wanting to operate on Sisko.
  • Supernatural
    • The early episode "Phantom Traveler" which appears to be a straight Monster of the Week episode with the brothers having to exorcise a demon who causes planes to crash For the Evulz. Not only do we learn later in the season that the one who killed the boys' mother and sam's girlfriend is also a demon but demons become the major threat for the next few seasons with the rise in demonic possessions being a major plot point.
    • When Adam is first revealed as a third Winchester brother who was kept from Sam and Dean, he doesn't appear to have any relation to the main storyline at all, and the show even lampshades how out of nowhere it seems by naming the episode "Jump the Shark". However, Adam ends up being extremely important to the resolution of season 5, particularly for the finale.

    Professional Wrestling 

    Traditional Games 
  • The Magic: The Gathering expansion Mirrodin had a villain named Memnarch, a golem driven mad by a weird, glistening oil. Memnarch was defeated, but the oil remained. It turned out to be Phyrexian oil, heralding the corruption of the plane of Mirrodin into New Phyrexia seven years later.
  • The New World of Darkness core rulebook began with a story about mechanical angels serving the enigmatic God-Machine. While popular, this didn't seem important until ten years later, with the release of the second edition, the God-Machine Chronicle, and Demon The Descent, both of which involve the God-Machine heavily.

    Video Games 
  • Ace Attorney
    • Case 1-2 features the death of Mia Fey and is the first to introduce us to DL-6. Both of these things are the two most important plot points of the original trilogy.
    • Case 2-2 looks at first glance as a way to give Maya some backstory. It also sets up the plot of Case 3-5.
    • Case 3-1 is the standard tutorial of the game. The villain is the Big Bad of the game.
    • Case 4-1 ends without a clear explanation of the motives for the murder and who the victim was. The villain is also the Big Bad and the case sets up Case 4-4.
    • Case 5-1 foreshadows Athena's post traumatic stress disorder. Additionally, the bombing and murder that makes up the trial interrupts Case 5-4 and while Case 5-1's villain is responsible for the murder, it was the Big Bad and the one responsible for the last two cases that set of the bomb.
    • Case 6-1 ends with the reveal that the Kura'in national treasure, the Founder's Orb, has gone missing. What happened to it forms a major part of the Case 6-5.
    • Case 1 of Ace Attorney Investigations features the villain stealing a file from Edgeworth's office. What said case file is for is revealed in the fourth case to have a big baring on the plot.
    • Investigations 2 has the first three cases. Case 1 features an attempted assassination of the president of a foreign country who is one of the Greater Scope Villains. The murderer in this case also has a connection to the Big Bad that gets revealed later. Case 2 introduces three important characters: another Greater-Scope Villain, the Big Bad and an assassin with connections to both. It also introduces the Central Theme of the game. Case 3 looks like it has little connection to the main plots of the other cases but it forms part of the main antagonist's backstory.
  • Dragon Age:
  • The first mission in the original Final Fantasy, where you have to rescue Cornelia's princess and defeat the evil knight Garland in a laughably easy battle so the King can build a bridge leading you to the town of Pravoka. Talking to the newly-rescued princess while in the throne room results in her thanking you and giving you a lute. At the end of the game, you learn that Garland has enacted a plan to create a time loop to escape his death and becoming the god Chaos. The lute is used to get into The Very Definitely Final Dungeon.
  • Golden Sun: Dark Dawn's tutorial dungeon, Tanglewood Forest, is built around the concept of using light and warmth to dispel darkness and the unnaturally-empowered creatures therein. Two-thirds of the game later, a supernatural Total Eclipse of the Plot happens, covering half of Angara with darkness that empowers monsters...
  • A lot of seemingly comical or nonsensical things in Hatoful Boyfriend take on greater importance in the Bad Boys Love route. Especially Anghel's entire route: his deranged ramblings, once the fantasy-JRPG metaphors are unraveled, include nearly everybirdy's backstories and motives in shocking detail.
  • In the original Kingdom Hearts, the story of the Deep Jungle world has Sora reacting to a slideshow picture of a large castle with an odd familiarity even though he'd never left the islands before, and Tarzan telling Sora, in response to the question of where he can find Riku and Kairi, "Friends here; *&&X%.", which turns out to mean that his friends are in his heart. During the games climactic level at Hollow Bastion, Tarzan's words turn out to be Foreshadowing since it's revealed that Kairi IS REALLY inside Sora's heart and since she came from Hollow Bastion, that was also the reason why the castle seemed so familiar to Sora.
  • In Kingdom Hearts Dream Drop Distance, Sora pays a visit to Prankster's Paradise where he meets Pinocchio. Xemnas mentions Pinocchio grew a heart and Sora questions why the Nobodies can't grow hearts as well. In The World That Never Was, it turns out Nobodies can grow hearts, which Xemnas knew all along.
  • In Mass Effect, there's a side mission that involves going to the Moon and helping shut down a rogue AI. The third game reveals that this was an early form of EDI, the AI on the second Normandy, who was recovered by Cerberus and rebuilt.
  • One of NieR: Automata's sidequests, "Amnesia", features an android who has, of course, developed amnesia and wants to find out who killed her comrades. It's revealed at the end of the sidequest that the amnesiac herself was the one who did it. Her true identity is a YoRHa unit E-Type, which stands for Executioner class: a type of YoRHa specifically designed to kill rogue androids. This E-Type couldn't bear the pain of killing her fellow androids over and over again, so she wiped her memories in an attempt to ease the pain, which only resulted in her going insane when she remembered. It's an interesting sidequest on its own, but it doesn't have much bearing on the overall plot...but if you do it, it makes The Reveal at the end of the game sting that much harder when you find out 2B is in actuality one of these E-Type units, and she doesn't exactly enjoy the job either.
  • In Pokémon Black and White, Team Plasma's attempt to steal the fossilized dragon from Nacerene Museum becomes this when you learn that they're searching for an ancient legendary dragon, and what they needed was something else in the museum namely, the unidentified pretty stone being used as a placeholder.
  • Likewise, the encounter with Team Flare on Route 10 and Geosenge Town in Pokémon X and Y turns out to be this. Initially, they don't reveal much reason for being there other than to study the strange stones in the area. In Geosenge, you see a Team Flare grunt run off towards a dead end in town and never come back. Later you find out not only is Team Flare's secret headquarters located in Geosenge town, but it's also the location of the Ultimate Weapon. Team Flare seeks to reactivate it using the energy from the stones on Route 10, which turn out to be the graves of Pokémon killed in war.
  • In Rayman Origins, after beating a level, you give your Lums to the Magician, who gives you Electoons and Lum Medals. This doesn't seem too special until The Reveal, where you find The Magician behind the machinery of Moody Clouds, using the Lums to power it.
  • Resident Evil 4 retroactively makes Resident Evil: Dead Aim important to the series' ongoing canon. High-roller businessmen were aboard the Spencer Rain in order to bid on Umbrella's bioweapon experiments, but Morpheus Duvall murdered them all, taking Umbrella's capital with it and forcing them into bankruptcy.
  • The World Ends with You has a chapter where you have to bring the Gatito fashion brand to the top of the trending charts and pitch the pin to the citizens of Shibuya. Other than the one Gatito pin you have only having the effect of slowing down Neku's movement, this chapter seems to be a benign tutorial on how to manipulate the trends chart. Two weeks later, Neku finds out that the pin is a brainwashing device set up by Megumi Kitaniji, who's trying to pull off an Assimilation Plot.

  • Gunnerkrigg Court seems to be using this heavily, as several chapters, characters and plot points that seemed to have nothing to do with the overall Myth Arc at the time (particularly Aly's transformation in "A Week for Kat") have taken on greater importance later, especially after the events of Chapter 20. Even the second chapter, which looks like filler, contained set-up for what is now confirmed to be an Aborted Arc.
  • Homestuck's intermission at first seems to be a completely unrelated, silly tangent that has no bearing whatsoever on the plot. Of course, everything in Homestuck is plot-relevant, and said intermission turned out to have a big impact on the trolls' session, especially after the EOA5 flash when Spades Slick kills Snowman and destroys their universe. In fact, the Intermission includes the first mention of the comic's eventual Big Bad. For some, as much as the first three acts could be considered this, appearing to be nothing more than a bunch of pointless gags, but in actuality setting up a lot for later on such as the bunny John receives as a birthday present, which ends up becoming incredibly powerful, reaching the hands of a villain, and in doing so causes at least half of the terrible things that happen during the kids' and trolls' sessions.

    Western Animation 
  • The Adventures of Puss in Boots features the episode "Copy Cat". A seemingly average Breather Episode in the season it takes place in involving Puss creating a clone of himself to resolve a Two-Timer Date plot. It's eventually revealed that this event caused an instability in the multiverse that ultimately leads into an Evil Twin of Puss In Boots taking over the Netherworld to become the Big Bad of that season.
  • Adventure Time:
    • The episode "The Enchiridion!", Princess Bubblegum sends Finn and Jake to retrieve the titular book. This is not a big deal until season 4 reveals that the book can opens portals to other universes. The Lich stole it from the heroes who then travels to a dimension where he plans to wish for the extinction of all life.
    • In the episode "His Hero", Finn and Jake meet their hero Billy and try to emulate his non-violent lifestyle. The episode itself is quiet forgettable but it has the first brief appearance of the Lich, who will be the Big Bad for the next seasons, along with the Gauntlet of the Hero and Billy himself has a key role in the finales of seasons 4 and 5 albeit a posthumous one.
    • The episode "The Creeps" seems like a random episode about a fake murder mystery. Except for the appearance of Shoko (Finn's past life) as a ghost as revealed in "The Vault".
  • Avatar: The Last Airbender has several.
    Azula: Who are you angry at?
    • "Nightmares And Daydreams" is pretty much a Filler Bizarro Episode- its A-plot is Aang getting sleep-deprived from stress about the upcoming invasion and beginning to hallucinate, and its B-plot is Zuko and Mai spending time with each other, cuddling adorably, and sneaking past the radar. Oh, and Zuko attends an offscreen war meeting, during which something happened that finally cemented his Heel Realization. We won't learn what happened at the meeting until the finale, but oh boy is it a doozy. Upon hearing Zuko's advice that the Earth Kingdom's people were tough and would keep fighting as long as they had hope and Azula's suggestion that they burn said hope to the ground, Ozai decided to use the Sozin's Comet power boost to utterly destroy the Earth Kingdom.
    Zuko: During the meeting, I was the perfect prince, the son my father wanted. But I wasn't me.
  • The Avengers: Earth's Mightiest Heroes! episode "Alone Against AIM" seems rudimentary at first, boasting a simple storyline in which Iron Man and some of his companions prevent AIM from stealing important Stark Industries data and armor. It does, however, contain at least two ties to the season's main arc. First, Iron Man introduces a new suit of armor, which he will continue to use up through the series finale. Secondly, Captain America (actually a Skrull in disguise) reveals to the other heroes during the aftermath that he managed to keep the data out of AIM's hands, but the Skrulls later use this information to implant a crippling virus into Iron Man's suit.
  • Beware the Batman:
    • "Attraction" is a break from the League of Assassins storyline before its resolution. However, it also introduces Batman's possible identity crisis and instability, which plays a huge role in the second half of the season.
    • "Nexus" introduces Harvey Dent, an important character in the latter half of the series. More importantly, the events of this episode parallel the events of the three-part season finale on a far larger scale.
    • "Games" has a rather self-contained plot involving Humpty Dumpty. Later in the series, we learn that the traumatic events of that episode caused Mayor Grange to resign, kicking off the mayoral elections that play a major role in the season finale.
  • The Camp Lazlo episode "The Engagement" contains ends with a joke where, after Jane's engagement falls apart, rather then recognize Lumpus' affection she starts flirting with the Navy Turtle, hoping to be engaged to him. The final season sees Lumpus attending their wedding and subtly crashing it, beginning his relationship with Jane.
  • Codename: Kids Next Door started its beard-growing with what just seemed like another of its early, one-off episodic stints, namely the episode where a baby network executive convinces the KND to let him use their satellite network, which turned out to be a plot to use his age-changing ray on the whole planet. The kids defeat the baby, but in The Stinger his age-changing device ends up in the hands of the Delightful Children...
  • The Detentionaire episode "28 Sneezes Later" seemed like a weird Bizarro Episode at first, with Lee apparently hallucinating for most of it and a B-plot that mostly served as a parody of Zombie Apocalypse films. However, as it turns out, Lee's little adventure did a lot of foreshadowing for things to come in the series, such as the fact that his immunity to the Prank Song was In the Blood. The B-plot also showed us that Brandy was more capable than she looked, setting up that she was going to become more than an annoyingly clingy "girlfriend" to Lee as the series progressed.
  • The Ed, Edd n Eddy episode "Ed, Pass It On" (from 2002) is about Eddy lying that his elusive older brother is returning to the cul-de-sac in an attempt to gain respect. When he supposedly does arrive (it's actually Sarah and Jimmy in disguise), Eddy reacts with absolute fear. Seven years later, the Grand Finale Movie reveals that Eddy's Brother is actually a sadistic bully who tortures Eddy for fun and all the stuff Eddy's been saying about him all these years were all lies so he can get respect from the other kids.
    • In the same episode, when Rolf gets the "news" that Eddy's Brother is coming, he barricades his farm and tells Eddy to tell his brother Rolf's chickens no longer exist. After watching The Movie, it makes you wonder what was he doing to Rolf's Chickens?
  • The events in Family Guy episode "The Cleveland-Loretta Quagmire" would haunt Cleveland for years to come, such as in "Love Blactually," and eventually led to the existence of The Cleveland Show.
  • Gravity Falls has some tremendous hints to its big mysteries hidden in episodes that otherwise aren't massively relevant to the plot. Season one's "Carpet Diem" is a "Freaky Friday" Flip episode, but includes some of the biggest hints to one of the show's mysteries. In the episode, we have two short moments where Stan discovers an old pair of glasses slightly different than his own, and is later seen sadly holding them. Fifteen episodes later, we have the Author's identity revealed to be Stan's brother.
  • Justice League was almost purely episodic for its first two seasons, and has several episodes which are used as the basis for the story arcs in later seasons:
    • "A Better World", in which an alternate universe version of the Justice League assassinates President Luthor and seizes control of the government, becomes the basis for the conflict in the first two seasons of Justice League Unlimited. The two-part finale of Superman: The Animated Series (which aired four years before) also played a big part in this. Lampshaded thoroughly in the commentary tracks for Justice League, along with a flashback to an even earlier episode of Superman.
    • "Twilight (of the Gods)" seems like a one-off until the two-part series finale, when Luthor, in an attempt to revive Brainiac, brings back Darkseid with Brainiac enhancements.
  • The Littlest Pet Shop (2012) first-season episode "What Did You Say?" has a pretty subtle one: One of the side effects of Blythe's cold medicine, as written on the bottle, is a temporary loss of the ability to talk to animals, implying there are people who can talk to animals other than Blythe. That Blythe is not alone would become a major theme for the final season and its Story Arc.
  • My Little Pony: Friendship is Magic:
    • Season 2 episode "It's About Time" is a typical slice-of-life episode whith Twilight having to learn not to worry so much about what might happen tomorrow after spending the week trying to prevent upcoming disasters. At the same time, it sets up two huge season-finale crises:
      • In that episode, Twilight had to bring Cerberus back to the gates of Tartarus where he belongs. In the Season 4 finale, we learn that Tirek, one of the most dangerous creatures imprisoned there, escaped during this time.
      • It also introduces a time-travel spell created by Star Swirl the Bearded. Pinkie Pie makes a point that it can only be used once, so you'd think it couldn't show up again, right? Except that, as demonstrated by the Season 5 finale, the spell, altered by a very skilled unicorn alongside the use of an Amplifier Artifact, can have absolutely devastating effects.
    • "Appleoosa's Most Wanted" is at first a self-standing episode in which the Cutie Mark Crusaders help an older stallion to find the real meaning of his Cutie Mark during one of their usual escapades to find their special talents. Later on in the season, it turns out helping other ponies realize their talents is their own talent.
    • The Season 7 episode "Campfire Tales" is a Vignette Episode where Applejack, Rarity, and Rainbow Dash each tell the tales of three legendary ponies by the names of Rockhoof, Mistmane, and Flash Magnus. Later on, "Daring Done?" primarily took place in a village heavily inspired by another legendary pony named Somnambula, and "A Health of Information" introduces yet another pony of lore called Mage Meadowbrook, whose research in a cure for a disease drives the episode's plot. The Season Finale revealed that all five of these ponies were (or are, rather) members of the Pillars of Equestria, led by fellow lore character Star Swirl the Bearded (who had been influencing the show's background since the second season).
  • Almost everything that happened across the Myth Arc of ReBoot can be traced back to the simple act of Bob loaning Mike The TV To Hexadecimal in "Painted Windows". Before that, the show was episodic.
  • Scooby-Doo! Mystery Incorporated:
    • The second episode, "The Creeping Creatures", has a trip to nearby Gatorsburg and a quick capture of some (fake) gator people, but the important part looked like a throwaway scene at first. A flickering sign spells The Dog Dies. A quick scare for Scooby? Nope. A command, or perhaps a piece of advice, and something close to being Arc Words. The quick references to gator mines and wells also seem a joke, but even in a world full of people in ghost costumes, that's clue pointing towards something unnatural.
    • "The Shrieking Madness" features a rather unexpected cameo from Harlan Ellison®, Adam Westing as himself and engaging in a spot of petty rivalry with a No Celebrities Were Harmed version of H.P. Lovecraft. It's an amusing cameo, but doesn't seem to be crucial to the series' Myth Arc. Until the series finale, that is... When the gang rewrites reality by erasing the Evil Entity from history, Harlan Ellison turns out to be the only person who remembers the old timeline, thanks to his experiments with speculative fiction. There series ends with him inviting the gang to solve mysteries under him as his he takes on the moniker "Mr. E".
  • Star Wars: The Clone Wars: "Senate Spy" may initially seem like padding, but it ends up kicking off a major arc about the second invasion of Geonosis, and ultimately leading to the first appearance of zombies on the show.
  • Star Wars Rebels
    • "Droids in Distress", the second episode, involves the Ghost crew, low on fuel and cash, taking a job to steal weapons from the Empire. They end up running into everyone's favourite droids, R2-D2 and C-3PO, on an undercover mission, and end up having to return the droids to Bail Organa — which, eventually, leads directly to the crew joining the larger Rebellion.
    • "The Call" has the crew encountering a pod of purrgil in a side adventure. However, come the Grand Finale, Ezra summons a large group of them, some of them the size of capital ships, in order to neutralize Thrawn's blockade around Lothal. The purrgil destroy Thrawn's fleet and jump away with Thrawn and Ezra to parts unknown, thus ending their stories in the show and setting up for a sequel show.
  • Steven Universe often has mundane sounding episodes which end up having major character or plot related impacts. For example:
    • "Steven's Lion": Steven adopts a pink lion. The Lion becomes a recurring character. In "Lion 2: The Movie", he takes Steven to a secret armory, and he can make a sword come from his head. "Lion 3: Straight to Video" shows that Lion can store things in his mane, and also has a video made by Steven's mother, Rose Quartz. Finally, "Rose's Scabbard" reveals that both the armory and the sword also belonged to Rose Quartz.
    • "Laser Light Cannon" had the Red Eye, a Monster of the Week that seemed to have no importance. In "Marble Madness", it was revealed to be a probe sent by Peridot.
    • The eighth episode, "Serious Steven" is another lighthearted romp where Steven and the Gems go to collect an artifact with little overall importance. Except for the mural on one of the pyramid walls, depicting the Diamonds positioned in opposition to Rose Quartz, with a yellow, blue, and white triangle with a smaller, pink triangle next to her that's not the shape of her Gem. The full significance of this image wouldn't be revealed until two seasons later, when Rose was revealed to have shattered Pink Diamond during the war for Earth.
    • "Keep Beach City Weird!" has virtually no importance to anything until the ending goes into meta Foreshadowing. Ronaldo exclaims to Steven Universe (the character) that "It can't be that simple! There has to be more to it than just... YOU!", which may as well be talking about the show at that point. Peedee than says that it's not simple because "Steven is only one part of the puzzle" and that everything is tied to a conspiracy by "Level 8 beings". Ronaldo then realizes that everything is indeed tied to polymorphic, sentient rocks, and he starts raving that "they're here to hollow out the earth! It's all part of the Great Diamond Authority! They can take on any form!" This turns out to be a major case of The Cuckoolander Was Right, making a statement of how the show was indeed not as simple as it first appeared and that there was more to it, all of it being exactly what Ronaldo described, over the horizon.
  • Transformers: Beast Wars
    • An episode near the end of the first season entitled "Before the Storm," which sets up the first season finale and a huge chunk of the second and third season subplots as well.
    • Similarly, the second-last episode of the first season of Transformers Animated, "Nature Calls", was an odd episode that involved "space barnacles", but it also set up for Megatron getting his body back in the season finale.
    • Also in Animated, the episode "Headmaster" seemed to just be another disconnected episode with a new human supervillain, except that the Headmaster would up responsible for (one of) Starscream's current predicament(s), as well as the introduction of Dirt Boss and the resultant effect on the Constructicons.
    • In Transformers Prime, "Convoy" and the human villains it introduces seem to have nothing to do with anything else going on in the show. When they return in "Operation: Breakdown", they've become much more relevant, focussing their agenda on the Transformers themselves and finding out what makes them tick.
      • Stronger, Faster at first seams to be the token Very Special Episode substituting steroids with artificial energon. In the third season the decepticon's own research into artificial energon creates a zombie horde that depletes half their forces. Even later it is crucial in the restoration of Cybertron.
  • The Venture Bros. takes this to an art form. Seemingly trivial details and bits of dialogue have a nasty habit of becoming the fulcrums to entire episodes, up to several seasons later. Case in point: In the Season 2 episode "¡Viva los Muertos!" Dr. Venture educates his newly-animated Venturestein with a series of videos depicting a Central American sweatshop. Three seasons later, in the episode "Venture Libre", we learn that Venturestein became rebellious because he recognized one of the boys in the videos when he was sent to quell a revolution.
  • X-Men: Evolution features an episode in Season Two where a previously-unseen mutant enacts some plot that completely stumps the heroes and leave them wondering what the hell THAT was all about. The end of the episode reveals he is attempting to free Apocalypse. This isn't revisited until Mesmero turns up again Season Three, becoming the major running plot for the second half of the season, and culminating in Apocalypse being the Big Bad of the final season.
  • The Young Justice episode "Denial" initially looks like a straightforward Villain of the Week outing. Ultimately, though it turns out that not only was aforementioned villain actually a member of the Light, the Big Bad group of the whole series, but he was the first member of the Light to appear in person. Adding to that, the episode launched the ongoing Dr. Fate subplot that would turn up again several more times during the season, hinted towards Red Tornado's ties to the Justice Society, and laid the groundwork for the Kid Flash/Artemis relationship as well.