History Main / MalignantPlotTumor

* [[HordeOfAlienLocusts The Vord]] from the ''Literature/CodexAlera'' series are a classic example of this. They're introduced in the first book as the nasty but apparently unintelligent and unimportant guardians of the MacGuffin of a SideQuest. In the second book, they prove to be ''very'' intelligent (though only collectively) and become a major threat, only to apparently be completely wiped out. In the fifth book, they're back with a vengeance, having been building up their forces massively in the background and forcing [[TheHero Tavi]], [[WorthyOpponent the Canim]] and [[MagnificentBastard Lord Aquitaine]] to team up to stop them.

* In perhaps the most pronounced example ever documented, outsider artist Creator/HenryDarger's autobiography ''The History of My Life'' begins with 206 pages of his early life, then digresses for 4,672 pages on a tornado nicknamed "Sweetie Pie". It's somewhat understandable, since he's referencing several actual deadly tornado systems he would have witnessed as a teen.
* The ''entire'' plot of ''Literature/TheLordOfTheRings'' essentially springs from a minor plot point (the ring) in ''Literature/TheHobbit''.

* For most of ''WesternAnimation/{{Wishology}}'', the [[TheDragon head]] of the MechaMooks was simply a recurring opponent. However, after seemingly falling into the background, he suddenly goes [[EnemyCivilWar rogue]] and [[TheAssimilator absorbs the entire planet]]. With the revelation that [[spoiler:DarkIsNotEvil]] he proves the trilogy's true BigBad. Considering all the parodies in said films, he is likely a direct ShoutOut to [[Film/TheMatrix Smith]].

** The {{Big Bad}}s of season 6 [[NotSoHarmlessVillain look like]] three fairly {{Harmless Villain}}s, but there's also a subplot about Willow being [[AddictiveMagic addicted to magic]], which is fairly minor at first. By the end of the season, one member of the trio has been FlayedAlive, and everybody is too busy trying to prevent Willow from destroying the world to care about the two others.

You are watching a movie, or reading a book and everything is going along swimmingly. There is an A-plot and maybe a [[TwoLinesNoWaiting B-plot]] and a [[ThirdLineSomeWaiting C-]] and [[FourLinesAllWaiting D-plot]] thrown into the mix too. While the storyline isn't too obvious, it's pretty clear that the climax is going to be with the BigBad that is the focus of the A-plot. But there is also a small E-plot, it's so small you might not even notice it, but as the story goes on, it grows and grows until the main characters are forced to completely forget about all the other problems and focus completely on this growing threat. Despite its dire sounding name, this trope can be used [[Administrivia/TropesAreTools with excellent results]]. Ergo, this might even be a ''Benign'' Plot Tumor.

* Creator/ValiantComics' 1990s revival of ''ComicBook/MagnusRobotFighter'' initially picked up right where UsefulNotes/{{the Silver Age|of Comic Books}} series left off, with a decadent upper-class humanity becoming increasingly dependent on robots and vulnerable to antisocial ones; the robots chafing under humanity's rule and sometimes becoming extremely dangerous; the vast slums on the Earth's surface, beneath the gleaming towered cities, where life is terrible; and Magnus trying to find a way to set things right for all three factions. It had always been a cool premise with a lot of potential, and at first the Valiant title explored it in much more depth then the original Creator/GoldKeyComics version had. ''Then the Malev Robots from space invaded,'' conquering Earth and derailing all of the above-mentioned premise. All that mattered after that was everybody fighting space robots.
* Over the course of Creator/DonnyCates' runs on ''[[ComicBook/VenomDonnyCates Venom]]'', ''ComicBook/{{Guardians of the Galaxy|2019}}'', and seemingly culminating in ''ComicBook/KingInBlack'', practically ''everything'' related to [[Characters/MarvelComicsSymbiotes Symbiotes]] is shown to be connected to their dark god, Knull. At first, it seems reasonable, being their creator, but it gradually becomes apparent that his scope is far greater. His decapitation of a Celestial led to the creation of Knowhere, and his first symbiote was stolen by a man who became [[Characters/TheMightyThorEnemies Gorr the God Butcher]], both in his origins issue. His control extends to the Exolon worn by Wraith, {{retcon}}ned into being symbiote prototypes. This is expanded into "pretty much anything darkness related" with the likes of [[spoiler:[[ComicBook/TheSentry the Void]]]] in ''King in Black''.

* The Z-List ''Film/TheBirds'' tribute/rip-off ''Film/{{Birdemic}}''. The first half of the movie is a rather bland romantic comedy. The second half is a laughably bad horror movie with terrible CGI birds.

* In the Creator/TimBurton ''Film/CharlieAndTheChocolateFactory'', this begins to surface as the tour is about to begin and it's revealed that Willy Wonka has a hard time saying the word "parents". Starting at about the halfway point of the film, the audience is privy to {{Flashback}}s of his childhood that reveal he had a FantasyForbiddingFather who ultimately abandoned him alternating with the tour scenes. Finally, Charlie is the last kid standing and Mr. Wonka intends to make him his successor...[[NotHisSled and the plot tumor turns out to stand in the way of the novel's ending]]. Mr. Wonka reveals that a condition of his offer is that the boy abandons his family, as his traumatic childhood has led him to think that it only holds one back. Charlie must decline, and Mr. Wonka slips into a depression of sorts even as Charlie's family's fortunes improve without him. Finally, Mr. Wonka consults Charlie, who convinces him to reconcile with his father. Only then does the HappilyEverAfter of the novel commence.
* The titular fight in ''Film/GodzillaVsKong'' is made out to be a huge deal that the previous three Franchise/MonsterVerse films have been leading up to, even though the mere ''notion'' that Kong and Godzilla have any relevant relationship with each-other wasn't introduced anywhere in the franchise until [[Film/GodzillaKingOfTheMonsters2019 the]] ''[[Film/GodzillaKingOfTheMonsters2019 third]]'' [[Film/GodzillaKingOfTheMonsters2019 film]]; and even then, it's only explicitly revealed that the two Titans' species were once rivals in the ''very last shot'' of that film's CreativeClosingCredits.
* The later two ''Franchise/TheMatrix'' movies seem to be about the showdown between the machines and free humans, but while those two sides are busy fighting, Agent Smith is busy replicating, and by the end, the warring factions must agree to a truce to deal with Smith. Almost a literal example, as Smith's replicating resembles the behavior of tumor cells a lot.
* ''Film/MontyPythonAndTheHolyGrail'' has a scene where a modern historian explains the setting of Arthurian-era Britain, but then has his throat cut by a passing knight on horseback. Just another absurd gag in a movie full of them, except that we see cutaways to the police investigating the crime throughout the film. They show up at the end and arrest Arthur and his retinue for it, conveniently preempting a big final battle scene that the production [[NoBudget didn't have the budget to stage.]]
* Cutler Beckett and the East India Trading Company in ''Franchise/PiratesOfTheCaribbean''. The company is more-or-less mentioned in passing in the [[Film/PiratesOfTheCaribbeanTheCurseOfTheBlackPearl first film]], before becoming much more of a threat in the following two films. By the time ''[[Film/PiratesOfTheCaribbeanAtWorldsEnd At World's End]]'' rolls around, the combined threat of Beckett and Jones was enough to ultimately unite the world's pirate forces, who up until then were crossing and betraying each other on a regular basis.

* ''Film/RedEye'' starts out like a romantic comedy before revealing that the male lead is a PsychoForHire here to present the heroine with a SadisticChoice. [[TrailersAlwaysSpoil If only the advertising campaign had understood this trope it might've worked.]]
* The main plot of ''Film/{{Stealth}}'' was about an [[AIIsACrapshoot AI fighter jet which goes rogue and attempts to start a nuclear war]] with subplots about the military contractors who wanted to figure out how it gained independence and [[TrappedByMountainLions one of the other fighter pilots being shot down over North Korea and running from the army]]. Halfway through, the AI is persuaded into giving up, making the military contractors the main plot point, before ''that'' is resolved anticlimactically so that the climax can take place in North Korea. At the very least, the way the runaway AI was [[TalkingTheMonsterToDeath talked down]] involved a big emphasis on [[ThePowerOfFriendship teamwork]], which is brought up again in the in-universe justification for the pilots breaking ranks and embarking on the rescue mission to Korea.

-->'''Schwartz''': "Well, Hank was a great detective all right."\\
'''Tanya''': "...but a ''lousy'' cop."
* In Creator/MNightShyamalan's ''Film/TheVillage2004'' halfway through the movie from focusing on Lucius' trying to unravel the village's secrets to Ivy going on a perilous journey to find medicine before it's too late. The village's secrets are still revealed as a result of Ivy's journey, however.

* ''[[Literature/TheCulture Matter]]'' by [[Creator/IainBanks Iain M. Banks]] starts off apparently about a deposed prince gaining back his throne from the EvilChancellor on a quasi-medieval planet, while more advanced aliens manipulate things behind the scenes. Then an archaeological dig is mentioned a third of the way through the book. Then later, the heroes find something in the city. Then with maybe four chapters left, the thing they find turns out to be SealedEvilInACan, whose first act is to kill all of the characters involved in the struggle over the throne. All but one of the surviving characters die trying to prevent it from [[EarthShatteringKaboom blowing up the world]].
* Creator/TadWilliams's ''Literature/{{Otherland}}'' involves a huge number of characters, and starts off rotating between their not-immediately-connected stories. The serial killer Johnny Dread is among this cast but doesn't play a particularly prominent role in the first volume. However, he grows in power and significance to be the main antagonist that everyone is fighting at the climax, even overshadowing the creator of the virtual world they're in.
* ''Literature/PerdidoStreetStation'' by Creator/ChinaMieville starts off looking light - the A plot is going to be a scientist helping a bird man to fly again, with a B plot of his girlfriend making a sculpture for a mysterious crime boss. But then one of the caterpillars the scientist was studying hatches and starts {{Mind Rap|e}}ing everybody. Everything else gets pushed to the side when it turns out that the moths are just about the deadliest thing in the world (even the LegionsOfHell are scared shitless of them).
* ''Literature/TheNightsDawnTrilogy'' by Peter F. Hamilton (especially book 1) seems to be about smuggling, politics, and revenge. That is until, halfway through the first book, out of left field, the dead come back to life.

* In ''Literature/ASongOfIceAndFire'' The Night's Watch and their undermanned defence of the Wall initially seems, compared to the epic civil war in the South, like a pretty minor plot which we're only seeing because the son of a main character is up there. It gets a bit more interesting when the Others show up, and later one of the claimants to the throne decides to assist the Watch, but the sheer world-endangering ZombieApocalypse nature of their threat is only gradually revealed to the reader and is still unknown or unappreciated by the vast majority of the characters. It takes the reader from rooting for whichever claimant they ''like'' the most to which one seems most able to defeat the Others.
* ''Literature/GentlemanBastard'': In ''The Lies of Locke Lamora'': The groups con of the Salvaras seems to be the A-plot. The Grey King is mentioned only as a background menace but eventually becomes the BigBad. The Salvara heist plotline is continued but is only important in how it related to the Grey King. Later books in the series make this plot structure more expected, with plotlines regarding heists and antagonists frequently intertwining.
* In perhaps the most pronounced example ever documented, outsider artist Creator/HenryDarger's autobiography ''The History of My Life'' begins with 206 pages of his early life, then digresses for 4,672 pages on a tornado nicknamed "Sweetie Pie." It's somewhat understandable, since he's referencing several actual deadly tornado systems he would have witnessed as a teen.

* While fans will [[FanWank debate]] endlessly about whether Creator/JossWhedon was winging it or not, most ''Series/{{Buffy|the Vampire Slayer}}'' seasons are good examples, particularly season 6. The BigBad [[NotSoHarmlessVillain looks like]] it's three fairly {{Harmless Villain}}s. But there's a subplot about Willow being addicted to magic, which is fairly minor at first, but by the end of the season, one member of the trio has been flayed alive, and everybody is too busy trying to prevent Willow from destroying the world to care about the two others.
** Seasons 2, 3 and 4 also show this pattern: a bunch of threats at the beginning of the season that end up being eclipsed by some bigger one.
*** Season 2 had the most rational explanation that there wasn't really a singular Big Bad throughout the season until [[spoiler:Angel [[MagnificentBastard went evil]]]], and once he did, everything else paled in comparison for the rest of the season...and maybe even for the rest of the series.
*** Season 2 also had to switch gears near the start because over the summer between seasons 1 and 2, the actor who played The Anointed One had grown too much to believably have him as the same unaging child vampire. The Anointed One was going to be the Big Bad of season 2.
* The 2000-era ''Series/{{Battlestar Galactica|2003}}'' drew most of its plots from conflicts between humans and Cylons, infighting within the fleet, and the overarching MythArc of finding a way to Earth. Along the way, however, seemingly minor details come up about the titular [[TheBattlestar warship]]:

* In Season 4 of ''Series/TwentyFour'', the raid on the Chinese embassy doesn't seem like a big deal at first, but wait until the end of season 5.
* The Kromaggs from ''Series/{{Sliders}}'' grew from a semi-recurring menace into the series' BigBad. It had little to do with the original premise and was poorly-received.
* Kirsten Cohen of ''Series/TheOC'' drank on-screen enough for Website/TelevisionWithoutPity to have started a "Kirsten Cohen drink watch '03." But at the end of season 2, she immediately switched from frequent wine drinker to inst-alkie complete with {{Wangst}}.

* ''Series/Daredevil2015'' and ''Series/TheDefenders2017'': This is how the Hand are built up. In season 1 of ''Daredevil'', two of the Hand's members, Madame Gao (one of the founders) and Nobu (subordinate to Murakami), are members of Wilson Fisk's crime ring and are using Fisk to help them acquire property for Midland Circle. Even though they don't mention they're part of the Hand, we know of the Hand's presence because of the ease that these two have at intimidating Fisk, while James Wesley is very uneasy being around Nobu. The first season of ''Series/IronFist2017'' adds more depth to Madame Gao's role in the Hand and also introduces Bakuto, and both of these people indicate that there is someone else pulling their strings who wants to meet Danny but don't mention Alexandra by name. Finally, we are introduced to the remaining Fingers (Alexandra, Murakami, and Sowande) in ''The Defenders''.
* The second season of ''Series/TrueBlood'' is mostly about Sookie helping Eric and the Dallas vampires find the missing sheriff, Godric. Meanwhile, there's a subplot going that has Tara moving in with a social worker who is secretly a maenad. For most of the season, the maenad, Maryann, isn't really much of a threat; she mostly just prances around holding sex parties and trolling Sam, committing a couple of murders while she's at it. However, after the Dallas plot is wrapped up, Maryann becomes the BigBad and the main cast must team up to [[spoiler:save the townspeople's souls from her control and stop her from killing Sam in a ritual sacrifice.]]
* In ''Series/DoctorWho'''s third (revived) series, the entire plot of Utopia and the plight of humanity becomes negligible when [[HijackedByGanon a certain tenacious character makes a surprise return.]] [[spoiler: Or so you think. In the next couple of episodes, just when you've gotten used to the idea that the certain tenacious character is the big threat, it turns out that we aren't quite done with the far-future plight of humanity -- and they aren't quite done with us...]]
* ''Series/{{Lost}}'' is naturally a big offender here. Just a small spoiler-free [[spoiler:(not)]] hint: The Final Season [[spoiler:and the two that preceded it]] is not really about castaways trying to survive after the crash and to get off the Island anymore.
* ''Series/{{Dexter}}'' Season 7: For the majority of the season, the focus is on Hannah [=McKay=] and Isaak Sirko, both jostling for position as Dexter's main antagonist. Meanwhile, in the background, Maria [=LaGuerta=] investigates the accusations leveled at her late friend and former lover, James Doakes. Come the final episode, [[spoiler:Isaak's dead, Hannah's in jail, and Maria's figured out who the REAL Bay Harbor Butcher is.]]
* In ''Series/BabylonFive'', mysterious alien vessels are introduced about halfway through the first season. Their first appearance is in the appropriately named episode "Signs and Portents." We don't even learn the name of the race that uses these strange-looking ships until after a few appearances. As the series progresses, we slowly learn more about them, until by the time Season 3 rolls around, the Shadows have become the series main antagonist, and the show's MythArc is in full swing.
* Had it not been cancelled halfway through the first season, ''{{Series/Crusade}}'' would have gone this way. The Drakh plague that dominated the storyline of the 13 filmed episodes would have been resolved by Season 2. The real MythArc, dealing with a conspiracy within [=EarthForce=], would come to the forefront. As it was, we only got the barest hints, which weren't even obvious as hints until WordOfGod provided some perspective.

** Dukat. His final arc started as the E-plot, something to give comic relief while everyone else was fighting the Dominion. Then things escalated. And again. And ag- say, did he just figure out how to free the [[GodOfEvil Pah-Wraiths]]? Which he [[ReligionOfEvil considered gods]] in a previous episode? Oh shit...
* In ''Series/KamenRiderGaim'', the protagonists are originally concerned with the competition between local street dance crews, though they do notice some odd monster attacks on the rise. About a third of the way through the series, the "dance crew" storyline is officially retired as the show focuses more on the invading monsters, and it's eventually revealed that this is a CosmicHorrorStory with the power to reshape the world at stake.
** This trope also applies to two of the secondary characters, Kaito and Mitsuzane. Kaito starts out as simply the head of a rival dance crew, who is a SocialDarwinist but otherwise pales in comparison to the other threats out there, and even frequently allies with our hero Kouta when their goals align. But when those other threats are dealt with, he becomes the FinalBoss since he, like Kouta, has been growing in power the whole time wants to use it to tear down and replace the world order. Similarly, Mitsuzane begins as Kouta's friend but gradually starts to hate Kouta, fall into madness, and make more extreme plans to shape the world to ''his'' whims. [[spoiler:Subverted when, just before the final battle, his schemes finally catch up to him and blow up in his face, leaving him psychologically broken and a non-threat.]]
* In season 4 of ''Series/OnceUponATime'' we have a minor subplot where Regina attempts to find out who wrote the magical storybook that says she is a villain under the belief that the author is responsible for her never finding permanent happiness despite being redeemed. The second arc of this season is all about a group of villains wanting to do the same thing and get their happy endings.
* In the season 2 and 3 of ''Series/The100'' we have a rather minor plot of Jaha looking for the city of light while the main protagonists focus on surviving on the Earth and their issues and alliances with the grounders. But when Jaha finds d city of light at the end of season 2 and returns to the camp at the debut of season 3, he starts to recruit for his group. By end of season 3 [[spoiler: they are the main threat with ALLIE the IA that brainwashes them as the BigBad of the season and all the protagonists must work together to defeat her]].
* Season 7 of ''Series/HomicideLifeOnTheStreet'', which is generally considered to be [[SeasonalRot the worst season of the whole show]], has a moment where Det. Sheppherd is beaten up by some suspects upon trying to make an arrest, had her gun stolen from her and her partner, Lewis, is nearly shot by them. What should have been a two or three episode plot ended up being a huge deal due to Lewis blaming her for nearly getting killed to the point of refusing to work with her for the rest of the season, he and the majority of the other characters, especially the women, believing her to be incompetent and her having no way to prove herself otherwise. It wasn't even until Bayliss called Lewis out on his (usual) unforgiving nature that he started to loosen up. Unfortunately by then, it was the SeriesFinale.

* Played for laughs in "Jack Sparrow" by Music/TheLonelyIsland. The song was supposed to be a generic club rap with a hook by Michael Bolton. However, Michael Bolton is so obsessed with the ''Franchise/PiratesOfTheCaribbean'' films that he keeps interrupting the rap to sing about them instead. He switches it to ''Film/ForrestGump, Film/ErinBrockovich'' and finally ''Film/{{Scarface 1983}}'' by the song's end. Turns out, he's a major cinephile.

* Frequently happens in ''TabletopGame/LegendOfTheFiveRings'' due to the audience participation model used to determine the storylines. Actions taken by players very early on in an arc can come to dominate the storyline late in its lifetime. The most memorable example is probably the first published story arc, The Clan War. It starts with the (at the time) six Great Clans coming into conflict with one another as they attempt to assume dominance while their emperor lies close to death, some of them consorting with the Empire's ancient enemy, the Shadowlands, in order to do so. The storyline concluded with the Shadowlands and its leader, [[GodOfEvil Fu Leng,]] firmly established as the undisputed [[BigBad Big Bad]] of the setting and the Great Clans forced to cease their war in order to wrest control of the empire back from Fu Leng and his undead hordes.
** A more subtle example occurred with the subsequent storyline, ''The Hidden Emperor.'' This storyline contained several confusing, seemingly-unrelated subplots with the abduction of Emperor Toturi I at its heart. At different points in the story, [[FaceHeelTurn the Dragon Clan]], [[AncientConspiracy the Kolat]], and the [[HijackedByGanon resurgent]] Shadowlands all seemed poised to emerge as the masterminds behind all the chaos. It was quite a surprise when the shapeshifting ninjas who had been a part of the setting since day one were revealed to be a [[HiveMind Hive Mind]] under the command of an [[EldritchAbomination Eldritch Abomination]] who had instigated everything as part of their master plan to [[EndOfTheWorldAsWeKnowIt unmake all of reality.]]

* In the ''VideoGame/{{Marathon}}'' trilogy, an evil [[SealedEvilInACan trapped inside the sun]] since forever is briefly mentioned once in a short piece of religious text of an alien planet in the second game, for the purpose of fleshing out a cultural {{backstory}} for the game's real plot. [[spoiler:Or so you think until it turns out that the "religious texts" were actually [[OhCrap accurate historical recordings]], and the enemy's eventual attempt to destroy the sun (with a likewise briefly mentioned WMD) releases the chaos god. The entire third game revolves around putting it back.]]
* The evil organizations in all of the main series ''Franchise/{{Pokemon}}'' games come into play as extremely minor obstacles in the way of the player's true quest (which is ToBeAMaster and GottaCatchEmAll), but swell in importance, numbers, and ferocity as the player progresses, and eventually eclipse the original quest in importance (at least for a little while).
** The [[VideoGame/PokemonBlackAndWhite fifth generation games]], as some feel, was the first generation to avert this, by basically having the plot involving the evil organization introduced in the first town you visit and remain important throughout the entire game.
* Despite being named after Sonic himself and being released as the main centerpiece of the franchise's [[MilestoneCelebration 15th anniversary]], [[BreakoutCharacter Shadow]] [[SpotlightStealingSquad and Silver's]] story-lines in ''VideoGame/SonicTheHedgehog2006'' have far more importance to the game's overall plot than Sonic's (which almost entirely consists of saving and losing the princess over and over again), to the point that by the [[TrueFinalBoss "Final Episode"]], the events of his story are practically a mere footnote.
* In ''VideoGame/UltimaIII'' the Great Earth Serpent was just an obstacle guarding the entrance to the Big Bad's castle, which you needed a password to get by. In ''Ultima VII Part Two: Serpent Isle'' you learn that the serpent in question was a cosmic force of balance, and removing it from its proper place threatens to destroy the entire universe as the serpents of Chaos and Order struggle unchecked.

* ''Franchise/BlazBlue'' introduces the Susano'o Unit in its first game, effectively a suit of magic armour operated by a human soul, with the potential to have RealityWarping abilities at full power. It gradually becomes clear that the "White Susano'o" Hakumen is, in fact, a LegacyCharacter, and that recurring villain [[OurGhostsAreDifferent Yuuki Terumi]] previously served as a "Black Susano'o" until he tore himself from the armour out of hatred for [[BargainWithHeaven the duties that come with the role]]. This doesn't really matter compared to the advent of things like [[HumanoidAbomination Izanami]], [[WorldWreckingWave Doomsday]], and [[PocketDimension the Embryo]] - until the end of the final game. After all other villains have been taken care of, Terumi [[spoiler:reveals himself as the disembodied spirit of the DestroyerDeity Takehaya Susano'o, who is free to [[OneWingedAngel reclaim his body]] now that the RestrainingBolt that prevented him from [[SatanicArchetype abandoning his job and destroying/conquering all reality]] is no longer intact.]]
* A common theme in the ''VideoGame/{{Fallout}}'' games: very rarely does the game's premise ([[VideoGame/Fallout1 finding a water chip for your vault]], [[VideoGame/Fallout2 finding a GECK]], [[VideoGame/Fallout3 locating your dad]], [[VideoGame/FalloutNewVegas finding the person who shot you]], or [[VideoGame/Fallout4 locating your kidnapped son]]) actually match up with the game's finale (fighting the Master, fighting the Enclave, fighting the Enclave again, fighting the Legion and/or NCR, or fighting the Institute). Often, the starting plot is completely resolved before the end of the first or second act, and external circumstances prevent you from [[NothingIsTheSameAnymore returning to your previous life]].
* In ''VideoGame/GoldenSunDarkDawn'', the first half of the game involves you trying to get a feather to fix your dad's flying machine so he can investigate the Psynergy Vortexes, all while you're being pestered by a couple of jackasses named Blados and Chalis. Then the two of them trigger the apocalypse, and you spend the second half trying to stop said apocalypse and bring them down. [[spoiler:TheStinger shows a very large Psynergy Vortex outside your house, showing that it might not have been such a good idea to completely ignore that whole plotline.]]

[[folder:Web Comics]]
* ''Webcomic/SluggyFreelance'' Dr. Schlock's evasion of Hereti-Corp dated back to when he was forced to work for them, and even when hC became the main plot, Schlock was still a minor supporting character. His fugitive flight from them took over more and more panels until "broken" [[spoiler: when he took over Hereti-Corp.]]
* Initially, ''Webcomic/CollegeRoomiesFromHell'' focused on three very different losers trying to live together while occasionally dealing with wacky supernatural baddies. At one point, TheDevil showed up, grabbed a character's soul, and then was quickly dispatched. The devil is mentioned another couple of times but doesn't appear again for a while. Then, it turns out one of the characters is a pawn in his plan to destroy the world, and all the other characters join forces to stop him.

* [[InvokedTrope Invoked]] and parodied in ''Webcomic/DarthsAndDroids'', where Anakin/Darth Vader is depicted as a minor NPC SpearCarrier ([[NominalImportance he isn’t even given a name at first]]) who gradually grows more and more important as the DM is forced to integrate him into the story as a result of the players going OffTheRails yet again. Eventually, he jumps to being a PlayerCharacter and from there [[spoiler:he becomes the BigBad responsible for Order 66 and the fall of the Republic, thanks to Annie being TheRolePlayer and taking his LawfulEvil alignment to its logical conclusion; since he’s supposed to be the TokenEvilTeammate, she plays him as being genuinely villainous to the point of [[TheStarscream betraying the rest of the party]].]]

* The ''WesternAnimation/FamilyGuy'' episode "Da Boom" features half-octopus Stewies multiplying out of control and eating most of the characters at the end.
* The first episode of Season 14's "Coon & Friends" trilogy in ''WesternAnimation/SouthPark'' was about Cartman trying to get Captain Hindsight to join his superhero team, with BP's recurring drilling accidents being the B-plot. Then BP unleashes Cthulhu and the last two episodes focus mostly on him, tying up Captain Hindsight's story in the second.
* ''WesternAnimation/TheSimpsons'' loves this trope, a good example is ''A Tale of Two Springfields''. It starts off being about a badger infesting a dog house, but when Homer tries calling animal control, he gets distracted by the fact that the area codes have changed. The badger looks through a window growling menacingly, but Homer shrugs it off, saying there are more important things to deal with now. In the end, when all of Springfield is focused on the resolution of the episode's major plot, an army of badgers seize the opportunity to take the town by surprise.
* In ''WesternAnimation/{{Futurama}}: Bender's Game'' the titular game starts as Bender tries playing an RPG and his imagination goes overboard. However, this is but a loosely connected sidestory to the main plot about dark matter (fuel). Then, right as that plot is reaching its climax, the messing with quantum physics caused the dark matter Bender had on his person to suddenly get sucked into his fantasy.
* ''WesternAnimation/TheFairlyOddParents'': For most of the "Wishology", the [[TheDragon head]] of the MechaMooks was simply a recurring opponent. However, after seemingly falling into the background, he suddenly goes [[EnemyCivilWar rogue]] and [[YouWillBeAssimilated absorbs the entire planet]]. With the revelation that [[spoiler:DarkIsNotEvil]] he proves the trilogy's true BigBad. Considering all the parodies in said films, he is likely a direct ShoutOut to [[Film/TheMatrix Smith]].
* ''WesternAnimation/SpiderManTheAnimatedSeries'': We get a double whammy, First with the portal machine that a MonsterOfTheWeek built, and the Carnage Symbiote, who is really only fought once or twice in the series. Not only is it used to [[spoiler: ''kill'' Mary Jane]] but the final battle of the show involves [[spoiler: Carnage coming out of nowhere and trying to use the machine to destroy the entire multiverse.]] WordOfGod supposedly says that a reason the show ended with an unresolved plot was that after [[spoiler: saving all existence]] they couldn't think of any more compelling plots for the webhead.
* In ''WesternAnimation/AvatarTheLastAirbender,'' you see a couple images of what looks like a turtle with a lion's head--there's a drawing of one in the MagicalLibrary, a statue of one in the Earth King's palace, etc. Given all the other MixAndMatchCritters in the show, you probably didn't even notice it. Well, in the GrandFinale, one suddenly shows up, reveals that [[TalkingAnimal it can talk]], and gives [[TheHero Aang]] a DeusExMachina so that he can DePower [[BigBad Ozai]] without killing him. One reason that this ending became so controversial is because of how out of nowhere this development felt.

-->'''Schwartz''': "Well, Hank was a great detective all right."
-->'''Tanya''': "...but a ''lousy'' cop."
* In Creator/MNightShyamalan's ''Film/TheVillage'' halfway through the movie from focusing on Lucius' trying to unravel the village's secrets to Ivy going on a perilous journey to find medicine before it's too late. The village's secrets are still revealed as a result of Ivy's journey, however.

* In the Franchise/MarvelCinematicUniverse, the plotline involving Thanos and the Infinity Stones steadily grew in importance. Phase One only involved the Tesseract in two movies (without revealing its greater significance) and revealed Thanos in TheStinger in one. Phase Two had three movies that each introduce a new Infinity Stone, with ''Guardians of the Galaxy'' also explaining what they are and giving more screentime to Thanos. Phase Three escalated even further, as the Avengers had realized what they were dealing with and Thanos had vowed to take action personally, culminating in ''Avengers: Infinity War/Endgame'' where they went head-to-head.

* The later two ''Franchise/TheMatrix'' movies seem to be about the showdown between the machines and free humans, but while those two sides are busy fighting, Agent Smith is busy replicating, and by the end, the warring factions must agree to a truce to deal with Smith. Almost a literal example, as Smith's replicating resembles the behavior of tumor cells a lot.
* Cutler Beckett and the East India Trading Company in ''Franchise/PiratesOfTheCaribbean''. The company is more-or-less mentioned in passing in the [[Film/PiratesOfTheCaribbeanTheCurseOfTheBlackPearl first film]], before becoming much more of a threat in the following two films. By the time ''[[Film/PiratesOfTheCaribbeanAtWorldsEnd At World's End]]'' rolls around, the combined threat of Beckett and Jones was enough to ultimately unite the world's pirate forces, who up until then were crossing and betraying each other on a regular basis.
* The first part of ''Film/TheBirds'' is mainly about the romance between Rod Taylor and Tippi Hedren, which ends up completely drowned out by the titular bird attacks by the end of the movie. Most people only know the film for the bird attack portion, leaving them quite confused by how long it takes to actually get to it.

* Many people forget that the first half-hour of ''Film/{{Psycho}}'' is a heist plot involving [[DecoyProtagonist Marion Crane]] embezzling money from her boss and making her escape. The entire plotline is completely abandoned once she's murdered partway through the film. The emphasis then transfers over to Norman Bates and how he's eventually captured.
* ''Film/RedEye'' starts out like a romantic comedy before revealing that the male lead is a PsychoForHire here to present the heroine with a SadisticChoice. [[TrailersAlwaysSpoil If only the advertising campaign had understood this trope it might've worked.]]
* In Creator/MNightShyamalan's ''Film/TheVillage'' halfway through the movie from focusing on Lucius' trying to unravel the village's secrets to Ivy going on a perilous journey to find medicine before it's too late. The village's secrets are still revealed as a result of Ivy's journey, however.
* The main plot of ''Film/{{Stealth}}'' was about an [[AIIsACrapshoot AI fighter jet which goes rogue and attempts to start a nuclear war]] with subplots about the military contractors who wanted to figure out how it gained independence and [[TrappedByMountainLions one of the other fighter pilots being shot down over North Korea and running from the army]]. Halfway through, the AI is persuaded into giving up, making the military contractors the main plot point, before ''that'' is resolved anticlimactically so that the climax can take place in North Korea. At the very least, the way the runaway AI was [[TalkingTheMonsterToDeath talked down]] involved a big emphasis on [[ThePowerOfFriendship teamwork]], which is brought up again in the in-universe justification for the pilots breaking ranks and embarking on the rescue mission to Korea.
* ''Film/MontyPythonAndTheHolyGrail'' has a scene where a modern historian explains the setting of Arthurian-era Britain, but then has his throat cut by a passing knight on horseback. Just another absurd gag in a movie full of them, except that we see cutaways to the police investigating the crime throughout the film. They show up at the end and arrest Arthur and his retinue for it, conveniently preempting a big final battle scene that the production [[NoBudget didn't have the budget to stage.]]

[[folder:Film]]

* ''Film/RedEye'' starts out like a romantic comedy before revealing that the male lead is a PsychoForHire here to present the heroine with a SadisticChoice.

* The ''WesternAnimation/FamilyGuy'' episode ''Da Boom'' features half-octopus Stewies multiplying out of control and eating most of the characters at the end.

* ''WesternAnimation/SpiderManTheAnimatedSeries'': we get a double whammy, First with the portal machine that a [[MonsteroftheWeek Villain of the Week]] built, and the Carnage Symbiote, who is really only fought once or twice in the series. Not only is it used to [[spoiler: ''kill'' Mary Jane]] but the final battle of the show involves [[spoiler: Carnage coming out of nowhere and trying to use the machine to destroy the entire multiverse.]] WordOfGod supposedly says that a reason the show ended with an unresolved plot was that after [[spoiler: saving all existence]] they couldn't think of any more compelling plots for the webhead.