History Main / InnocuouslyImportantEpisode

** ''Film/AvengersAgeOfUltron'' may seem like a VillainOfTheWeek episode at first, but the events of the film have serious repercussions for the MCU, to the point of having a ripple effect (it is the catalyst for virtually everything that makes up the "Phase 3" slate in some form or another). The casualties resulting from the fight in Sokovia leads to the Sokovia Accords being established and the Avengers [[BreakingTheFellowship splitting up]] in ''Film/CaptainAmericaCivilWar'', and the main antagonist of that film [[spoiler:lost his family in the battle at the end of ''Ultron'' and wants revenge]]. By the time ''[[Film/AvengersInfinityWar Infinity War]]'' starts, the heroes are still divided, which WordOfGod says [[TheBadGuyWins is why Thanos won]]. Even in more self-contained films like ''Film/SpiderManHomecoming'' and ''Film/AntManAndTheWasp'', and television shows like ''Series/AgentsOfSHIELD'', the Accords have an impact.
*** ''Age of Ultron'' is also the point where the original team disbands and Cap's Avengers team takes over. It isn't until ''Film/AvengersEndgame'' that [[PuttingTheBandBackTogether the band truly gets back together]].

* ''Fanfic/TheBoltChronicles'': “The Wedding Reception” proves to be the catalyst for shipping Bolt and Mittens in a later fanfic. Made clear in “The Ship,” where this earlier story’s [[DanceOfRomance dance between the two characters]] is referenced as an establishing factor for Mittens’s growing attraction to Bolt.

->''"...I've been stuck in the Quantum Realm since ''Film/AntManAndTheWasp'', and guess what, the events of that film contain the secret to solving this entire decade-spanning narrative arc! In other words, FUCK ALL Y’ALL WHO DIDN’T SEE MY MOVIE, UNNECESSARY FILLER MY TINY ASS"''

* ''ComicBook/SevenSoldiersOfVictory'': Creator/GrantMorrison's ''ComicBook/SevenSoldiers'' 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 ''[[ComicBook/BatmanGrantMorrison Batman Incorporated]]'' as a sinister organization.

** The ''ComicBook/SecretWars1984'' Crossover contains a small subplot where Spider-Man's costume is damaged and he needs to get a new one. He finds a neat black costume that enhances his powers and looks a bit like the newly-introduced Julia Carpenter's. Just an excuse to get the character a new look, right? Well, yes, until later when the black look proved unpopular and the writers needed to walk back on that decision, which they chose to do by revealing that the black costume was alive and making it a significant member of Spidey's rogues gallery as ComicBook/{{Venom}}.

** The ''ComicBook/SecretWars1984'' Crossover contains a small subplot where Spider-Man's costume is damaged and he needs to get a new one. He finds a neat black costume that enhances his powers and looks a bit like Jessica Drew's. Just an excuse to get the character a new look, right? Well, yes, until later when the black look proved unpopular and the writers needed to walk back on that decision, which they chose to do by revealing that the black costume was alive and making it a significant member of Spidey's rogues gallery as ComicBook/{{Venom}}.

** One of the biggest instances of this was Season 3's "Let's Get Together", which contained a random joke about there being only forty-nine states and Florida not existing for some reason. Season 10 reveals that this is because [[spoiler: the Director sunk Florida so that no one would notice the disappearance of Agent Florida, also known as Captain Butch Flowers]].

** For the first Hascon, Magic released a set of cards representing other Hasbro properties. One of these was for [[Franchise/{{Transformers}} Grimlock]]. One side was a Dinosaur (a then unused type), and it was three colors: red, green, and white. Since it's silver bordered (non-canon and not legal in official events), no one thought much of it. But a couple of months later, Ixalan was released, where Dinosaurs were a major theme, and they were in red, green, and white.

* In ''Literature/ATaleOfTwoCities'' there is an early chapter that concerns a young lad observing a grave robbing. It's very atmospheric but has no connection to the plot whatsoever. Until a few hundred pages later when it is absolutely vital. Considering Dickens wrote his books as serials that's some top quality plotting right there.