For almost a full season, the plucky folks who [[WeHelpTheHelpless help those in need]] have defeated MonsterOfTheWeek after MonsterOfTheWeek, protected the space-time continuum from invading aliens, stopped an {{Antimatter}} explosion from removing North America from the face of the planet, and saved the [[OurPresidentsAreDifferent President]].

Now, however, they are vexed by someone who seems to know their strengths, their weaknesses, and everything in between. They're outmaneuvered, outnumbered, and outsmarted. The season ends with the villain gloating over them, saying their most dangerous tasks up to that point have simply been tests he has engineered.

The Arc Welder cometh.

ArcWelding is a retroactive form of ContinuityCreep that occurs when a series which has heretofore been episodic {{retcon}}s itself so that it's all linked in a StoryArc. The most common approach to ArcWelding is probably when one antagonist, hidden up to that point, is responsible for all the major threats the protagonists have faced thus far.

Alternatively, several arcs might be revealed to part of a larger MythArc. This is rarer, possibly because it's harder to do well and shows that would benefit from it might not last long enough to play out the {{retcon}}.

Arc welding is different from StoryArc or MythArc because it is always retroactive. Series that start out with a StoryArc or MythArc already in place generally aren't welded. If something were already part of an arc, it wouldn't need welding.

The creators may be simply putting unrelated crap together for the sake of using up the budget now that they're renewed. It can be also be a stroke of brilliance, the creators now realizing an underlying theme of their work on the series thus far. Lastly, ArcWelding itself can be plotted from the beginning, as TheReveal. In the absence of the confirmation provided by the WordOfGod, ArcWelding is YMMV.

Compare CanonWelding, which ties together different series, and InnocuouslyImportantEpisode, which retroactively ties a seemingly unrelated event into an existing StoryArc. See also MetaOrigin, PatchworkStory.

[[IThoughtItMeant Has nothing to do with welding metal using arcing electicity.]] For info on that, go [[http://en.wikipedia.org/wiki/Arc_welding here]]. For a minigame on that, go to ''VideoGame/MetroidPrime''.

----
!!Examples

[[foldercontrol]]

[[folder: Anime and Manga ]]
* ''Manga/{{Bleach}}'': Was the plot up to BigBad Aizen's defeat a self-contained arc unconnected to the Thousand Year Blood War? Hell no! Aizen's deeply involved in many of the events that set up the War, but the Final Arc's BigBad was secretly involved in many earlier events as well. While the first arc appears to be a protracted chess game between Aizen and Urahara, the final arc answers the question of ''who had provided the chessboard''. The final arc connects events as disparate as the death of Ichigo's mother, Rukia's execution, Ichigo's substitute shinigami badge, Aizen's hollowfication experiments, Ryuuken's hatred of Quincies, and more. WordOfGod has indicated that the arc welding actually occurred at the end of the Soul Society arc when Creator/TiteKubo realised how to end the story on the basis of what he'd written up until that point. This discredited a fan theory that the length of the Arrancar Arc was a result of Kubo stalling because he hadn't figured out how to end the plotline. Thus far, ReWrite {{RetCon}}s have been avoided, although several events (most particularly Masaki's death) have had to be {{Revision}}ed.
* ''VisualNovel/HigurashiNoNakuKoroNi'': [[spoiler:Each arc is an alternate reality, but they're ''still'' in chronological order from Rika's perspective.]]
* A minor ''Manga/{{Naruto}}'' example: A {{Filler}} episode revealed that Mizuki attempted to steal the scroll of kinjutsu on [[BigBad Orochimaru's]] orders. This revelation occurred around episode 160 or so, and Mizuki stole the scoll in episode 1.
** A major ''Manga/{{Naruto}}'' example: Madara Uchiha is apparently largely responsible for/connected to the origins of Naruto (he unleashed the fox before it was sealed in Naruto), Sasuke (he helped Itachi with the Uchiha massacre), the entire Leaf Village (founder of one of the two clans it started with), and potentially many more elements of the story given his long tenure of FakingTheDead and being TheManBehindTheMan
*** DoubleSubverted- Tobi was never the real Madara to begin with. He is still responsible for the Kyuubi attack and the Sasuke and Itachi stuff, and a whole lot of other things, but several others he took credit for were actually the product of the real Madara's schemes or actions, such as implanting the Rin'nengan in Nagato. Tobi was Madara's apprentice and hijacked his plans.
** Not to mention that the Sage of the Six Paths, besides being the first guy with the Rinn'egan as well as creating the whole ninja world as it is (what he is initially mentioned for), also is source of the Senju and the Uchiha clans, the guy who split the almighty ten-tailed beast into the more familiar one to nine-tailed beasts, creating the MOON on the whole process. Busy guy.
* ''Every'' subplot in ''Anime/ExcelSaga'', which were all PlayedForLaughs, actually got tied together in the [[GainaxEnding surprisingly serious finale.]]
* In ''Anime/SailorMoon'' Creator/DiC tried to do this to all the bad guys that appeared during the second season. Then later [[spoiler: Creator/NaokoTakeuchi did this with the bad guy ''Chaos'' at the end of the [[Manga/SailorMoon manga]] who was supposedly responsible for the appearance of all the previous {{Big Bad}}s]]
* ''TenjhoTenge''. Every bad thing that ever happened to anyone turned out to be the work of [[spoiler:the protagonist's dad]]. Even the stuff that happened centuries ago.
* ''Anime/YuGiOhGX'' has this with season four, where it is revealed that the release of the Sacred Beasts, the Light of Destruction, and Yubel's schemes were all used by the final BigBad Darkness for...something.
* ''Anime/YuGiOh5DS'', the villains of the first major story arc are Roman Godwin and [[spoiler:his brother Rex]], who are revealed to be responsible for the Zero Reverse incident that severed Domino City in two The next season revealed Roman's turn to evil was engineered by the AncientConspiracy Yliaster as a plot to destroy Domino City with Zero Reverse. After the three leaders of Yliaster were defeated, the founder of the organization, Z-one, appeared as the final antagonist of the series, picking up the trio's plans to destroy Domino.
* Chapter 170 of ''Manga/YuYuHakusho'' confirms that [[spoiler:everything that happened in the series was a result of ''King Enma's'' actions. He created falsified reports of demon crimes in the human realm, let evil demons into the human realm, and even brainwashed innocent demons for his Spirit Detectives to finish off, increasing Enma's reputation within Spirit World, since the Spirit Detectives were under his command. This gave Enma the authority to erect a barrier between the three realms, as supposed demon "crimes" would create the illusion that this was a righteous act, and not totalitarian, since the spirit energy unused by humans was a valuable resource to the Spirit World.]]
* ''PokemonSpecial'' tends to do this. Both good guys and bad unexpectedly show up in later arcs with gambits ahoy, but FRLG and Emerald take the cake. FRLG was a result of all the previous arcs while Emerald was a direct consequence of FRLG. For reference, Emerald was the ''sixth'' arc, and Pokemon in general rarely bothers with continuing plots across multiple games/series/whatever.
** Volumes 29 (climax of Emerald) and 38 (climax of Diamond and Pearl, beginning of Platinum) brought together and resolved so many plot lines from different arcs to the point that the {{HSQ}} was reached.
* Happened quite a lot in ''FistOfTheNorthStar''. A few volumes after Kenshiro's TokenMotivationalNemesis Shin was killed off, it is revealed that the reason why he turned on Kenshiro in the first place was because Ken's stepbrother Jagi (a later villain) persuaded him.
* TheTatamiGalaxy is built around this trope.
* ''PrettyCureAllStars DX 3'' did the same thing the manga ''Manga/SailorMoon'' did with Black Hole. Though since ''DX 3'' is mostly non-canon to the series they're connected to, it kinda really doesn't count.
* This is pretty much the whole reason the ''CrossboneGundam'' manga exists: without it, ''GundamF91'' and ''VictoryGundam'' come off as two unconnected stories that just happen to be set in the UC timeline. With it, the stories are tied together into a larger overarching narrative with the Jupiter Empire and its aristocratic oligarchical philosophy as TheManBehindTheMan of both the anime series' {{Big Bad}}s.
[[/folder]]

[[folder: Comic Books ]]
* ''Series/BuffyTheVampireSlayer'':
** The end of Season 8 sets up the the background of {{Fray}}, written 10 years earlier.
** Also, when Whistler shows a vision of the future to come in a world without magic, it's clearly the world of {{Fray}}, if you notice the hovercars.
* ''ComicBook/CerebusTheAardvark'' did this ''a lot''. There were very few minor, throwaway characters. Just about anyone who talked to Cerebus at some point is revealed to be important to the plot somehow.
* The comic ''ComicBook/{{Transmetropolitan}}'' starts its MythArc with issue #13 (the Year of the Bastard storyline), but starts ArcWelding sometime around issue #30. Though it takes a while, events from the first issue are eventually revealed to have had an impact all the way to the last.
* One of the highest quality examples of this is Creator/DonRosa's ''ComicBook/TheLifeAndTimesOfScroogeMcDuck'' series, which takes every random reference CarlBarks ever made to Scrooge's past and puts together a comprehensive, sensical and engaging character biography. If the Eisner award is to be believed, it ''really'' worked.
* GeoffJohns has been doing this in the Comicbook/GreenLantern books, introducing an "emotional spectrum" that people can draw power from. The Green Lantern Corps fall square in the middle at green willpower; with red rage, orange avarice and yellow fear on one side and blue hope, indigo compassion, and violet love on the other. Not only are existing characters being tied into the spectrum (villainess Star Sapphire tapping into love energy, for example), but Johns has established whole rival corps for each (like yellow ring-wielder Sinestro starting his own Sinestro Corps of fear).
** It all started with his revival of Hal Jordan. The Retcon that explained away Hal's villainy also accounted for the periods of self doubt the character had been through, the graying of his hair, the reason the Spectre chose him as a host, and the reason why Hal was tempted by the power he stole while Kyle wasn't.
* When Marvel finally decided to fully reveal {{Wolverine}}'s [[ExpansionPackPast long and complicated]] origin story, it turns out that just about every bad thing that ever happened to him was orchestrated by a single figure known as Romulus.
* James Robinson's ''Comicbook/{{Starman}}'' managed to provide a coherent connection between the [[LegacyCharacter various characters who had used that name]], even though with one or two exceptions, none of them [[InNameOnly had any relation, or indeed even the same powers]].
* In ''[[Comicbook/UltimateSpiderMan Ultimate Spider-Man]]'', several {{Batman Cold Open}}s involving him fighting some villain who attacked "Roxxon Industries" were welded together when the CEO of that company (a person rather lacking in common sense) hired some mercenaries to bring him in for questioning about why he was fighting those people.
* Creator/KurtBusiek's ''Comicbook/AvengersForever'' story indulges in arc welding throughout, revealing that [[spoiler: every action ever taken by the villain Immortus was done in the interests of preventing the destruction of humanity by the Time Keepers. A number of seemingly unrelated plotlines turned out to have taken place under the influence of Immortus.]]
* One storyline of ''ArchieComics'' was the result of the events in previous stories: over the past couple of months, Jughead has experienced cranial injury from different objects (box of comic books, flamingo statue, typewriter, football, and a [[ItMakesSenseInContext ball of hamburgers]]). Somehow this causes his body metabolism to go in reverse; wherein usually any food he eats is instantly digested (explaining why he stays so thin), all the foods he eats now turn into fatty tissue, resulting in Jughead gaining a lot of weight overnight.
* ''[[Comicbook/ArchieComicsSonicTheHedgehog Sonic the Hedgehog]]'': During the "Enerjak Reborn" arc, [[MadScientist Dr. Finitevus]] reveals how everything he's done since his introduction has been part of his grand plan to create a new [[PhysicalGod Enerjak]]. It's also revealed that he was the (at the time) unnamed Echidna scientist who attempted to return Chaos Knuckles to normal by draining his power (the backfire of which is what rendered him [[EvilAlbino albino]]).
** Issue 224 reveals how several seemingly unrelated events during the FillerArc following the defeat of the Iron Dominion actually tied into [[BigBad Eggman's]] plan to [[spoiler: create a new [[FlyingAircraftCarrier Death Egg]]]].
** Issue 233: many of [[spoiler: Geoffrey St. John]]'s past actions are shown in a new light, as it's explained that he was working on a master plan to [[spoiler: make Ixis Naugus king of Acorn]].
** When the [[QuirkyMinibossSquad Destructix's]] backstories were revealed, a bit of this was applied to Sergeant Simian and Predator Hawk. They were shown to, in the past, have been members of the Gorilla Guerillas and the Battle Bird Armada (respectively), groups that were introduced after they were, but before the story arc that revealed their past memberships.
* An early story in the first ''ComicBook/{{Deathstroke}}'' series revealed that a character who had appeared once in a flashback story years earlier had in fact been seeking vengeance on Slade for years and was responsible for the kidnapping and maiming of Slade's younger son Joseph and the recruitment of his older son Grant for an experiment that would kill him.
* In ''ComicStrip/NonSequitur'', Wiley frequently used three separate sets of recurring characters: {{everyman}} Joe and his drinking buddy, Bob, BrattyHalfPint Danae and Sunday-only character, diner-owner "Offshore" Flo and her tall-tale telling patron, Eddie. Eventually, after years of the characters appearing in their own spheres, Wiley brought them all together: Joe and Bob are brothers, Flo is their mother and Danae and her younger sister are Joe's kids. (Eddie's still just "Eddie").
* Pretty much everything in [[Comicbook/GrantMorrisonsBatman Grant Morrison's run on Batman]] ties back to either Dr. Hurt and the Black Glove, or [[spoiler: Talia]]'s Leviathan organization.
* Another Batman example: the climax of the ''Black Mirror'' arc reveals that [[TheSociopath James Gordon Jr.]] was involved, one way or another, in pretty much ''everything'' villainous that occurred over the course of the arc. He also implies that he was the one who inspired SelfDemonstrating/TheJoker to cripple Barbara back in ''Comicbook/TheKillingJoke'', though it's unclear if that's true or if he's just screwing with her.
[[/folder]]

[[folder:Fan Works]]
* Dr. Brainstorm from ''Fanfic/CalvinAndHobbesTheSeries'' [[BlatantLies claims]] to have done this in order to build the [[DoomyDoomsOfDoom Doom]] [[SpaceStation Satellite]].
** Played straight in "Our Solemn Hour", [[spoiler: where [[BigBad Holographic Retro]] reveals he was behind the power outage in "Surge", the return of [[{{Technopath}} Electro]] in "Part Three", the "save Aankor" plan in "Invasion", and the FreakyFridayFlip in "Bodyswap" (though he intended it to [[LaserGuidedAmnesia erase their memories]]).]]
* The ''FanFic/HarmonysWarriors'' series of stories does this to tie together the stories based on the X-Men movies and those based on the Franchise/MarvelCinematicUniverse: Gustav, the BigBad of ''X-Questrians: First Class'', is revealed in ''Captain Equestria'' to have been a member of HYDRA back in the day, serving as Hoity Toity/Red Skull's [[TheDragon Dragon]].
* In the ''Fanfic/PonyPOVSeriesChaosVerse'', the BigBad [[spoiler: [[EnemyWithout Nightmare Phobia]]]] is revealed to be behind nearly every problem the Mane Six have for most of the show up to "Luna Eclipsed" (excluding Discord) by [[ManipulativeBastard manipulating their emotions]] to make them act in self-destructive ways.
* ''Fanfic/ReimaginedEnterprise'' puts together many different disconnected references and plot points from ''Franchise/StarTrek'' canon into new stories.
* ''Fanfic/TheLionKingAdventures'':
** [[spoiler: Death]], the BigBad of Series 3, reveals in ''Darkness Falls'' that he was directly responsible for ''everything'' that happened to Simba and his friends throughout the series.
** ''The End'' reveals that Series 5 BigBad [[spoiler: [[GodIsEvil The Writer]]]] is the UltimateEvil who created every other villain in the series, all for no other reason than [[ForTheEvulz his own amusement]].
* In the ''FanFic/FacingTheFutureSeries'', it's revealed in ''A Family Thing'' that [[ArchEnemy Vlad]] was behind Vortex and Nocturne's escape from Observant custody, and their subsequent actions, in ''Hearts and Minds''.
[[/folder]]

[[folder:Film]]
* Rare film example: in ''Film/{{Scream 3}}'', the killer, [[spoiler: Roman]], reveals that he was responsible for the events of [[Film/{{Scream 1996}} the first movie]], being the one who inspired [[spoiler:Billy]] to start killing. This would also make him indirectly responsible for the events of [[Film/{{Scream 2}} the second movie]] as well.
* [[Film/TheHowling Howling VII]] ''tried'' to do this, and actually did an admirable job. Unfortunately, the director chose to have the exposition delived in massive InfoDumps. The AgonyBooth had a field day with it:
--> ''If you do, put this story in several five-minute segments. We wouldn't want to exhaust the poor Inspector, would we?''
* In the Franchise/MarvelCinematicUniverse, the later Phase One films dealt with an object of power called the Tesseract and TheStinger to ''Film/TheAvengers'' revealed that [[spoiler:Thanos]] was that film's BiggerBad. TheStinger of ''Film/ThorTheDarkWorld'' would then tie those two together with its own MacGuffin, the Aether, when it stated that [[spoiler:the Tesseract and the Aether are both Cinematic Universe versions of [[ComicBook/TheInfinityGauntlet Infinity Stones]]]], which [[spoiler:Thanos]] has historically been involved with in the comics.
** In a smaller instance, in the first ''[[Film/IronMan1 Iron Man]]'' movie we are told that Howard and Maria Stark died in an accident when Tony was younger. Not much thought is given to this since unfortunately, car accidents are a common occurrence in real life. Then, years later during ''Film/CaptainAmericaTheWinterSoldier'', we find out that [[spoiler:the accident was deliberately caused after the Starks were targeted for assassination by HYDRA]].
[[/folder]]

[[folder:Literature]]
* Literature/SherlockHolmes. It was revealed, in the first of the two stories by Creator/ArthurConanDoyle to directly feature Moriarty, that the master villain had been involved in several of Holmes' cases before, but had simply never been mentioned until then.
* ''[[ASeriesOfUnfortunateEvents Lemony Snicket: The Unauthorized Autobiography]]'' played this for laughs. Most of the book consists of explaining how everything that had happened up to that point in the series was related to the VFD in various ludicrous ways.
* Franchise/DoctorWhoExpandedUniverse:
** The Literature/DoctorWhoMissingAdventures novel ''Venusian Lullaby'' takes a lot of the [[RunningGag throwaway one-liners]] the Third Doctor used to make about his adventures on Venus (that the Venusians sing lullabies, play hopscotch, etc.) and makes a coherent alien race out of them (living about a billion years in the past, when Venus might have been habitable). They're radially symmetrical and move by hopping. Oddly, no mention is made of the oft-referenced "Venusian Aikido" (at least by that name), nor how he might have learned it from such odd creatures.
** The Literature/PastDoctorAdventures novel ''Divided Loyalties'' establishes that the Doctor was part of a clique in the Prydonian Academy on Gallifrey with the other renegades featured in the original series (the Master, the Monk, the War Chief, the Rani and Drax), Vansell (introduced in the [[AudioPlay/BigFinishDoctorWho Big Finish audio drama]] ''The Sirens of Time'' earlier that year), two new characters (Jelpax and Millenia), and Rallon, who is revealed to have been posessed by the Celestial Toymaker, who used his body in the First Doctor serial by that name.
** The Literature/DoctorWhoNewAdventures novel ''Original Sin'' establishes that [[spoiler:Tobias Vaughn from "The Invasion"]] was responsible for various advanced technologies that plagued the Third Doctor, and also created the glitterguns from "Revenge of the Cybermen".
* Many Franchise/StarWarsExpandedUniverse sources tie in many of [[BigBad Palpatine's]] and especially [[TheThrawnTrilogy Thrawn's]] actions as being to prepare the galaxy for [[NewJediOrder the Yuuzhan Vong invasion]]. The degree to which this is accepted by fans varies- it's pretty much considered canon for Thrawn's motivation, but most see Palpatine as just using it as an excuse.
** More recently, Jacen Solo's change of heart in ''Literature/LegacyOfTheForce'' is seemingly being tied to new BigBad [[EldritchAbomination Abeloth]] in ''FateOfTheJedi''.
** Another example is Cade Skywalker's unique abilities in ''StarWarsLegacy''. His ability to sense vulnerable fractures has been tied to Mace Windu's sense for more metaphorical "shatterpoints", and his ability to heal serious injuries and death using the Dark Side is uncannily close to what Palpatine claimed Darth Plageius could do in ''Revenge Of The Sith''. And considering that other sources hint that Plageius created Anakin, it may be connected to that too... [[spoiler: though that was {{Jossed}} in the Darth Plageius novel. Anakin was created as a backlash against Plageius's machinations.]]
** Back to the subject of Abeloth, the final ''Fate of the Jedi'' novel reveals that she's connected to the Son, the Daughter, and the Father, the living embodiments of the Force first seen in ''WesternAnimation/StarWarsTheCloneWars''.
* This sort of thing is quite common in StarTrekNovelVerse books:
** The ''Series/StarTrekTheNextGeneration'' novel ''Q & A'' has every Q-episode of ''TNG'' as being part of a long term plan to [[spoiler: prepare Picard for meeting the beings that sit in judgement over the universe, and convince them it's worth saving]]. Except "Q-Pid". That one he just did for the hell of it. Or possibly for the FoeYay.
** Similarly, the ''Series/StarTrekTheNextGeneration'' novel ''Q-Squared'' implies that almost all the temporal anomalies encountered by Picard and his crew were also the work of Q - and goes on the add a relationship between Q and one-shot villain Trelane from ''Series/StarTrekTheOriginalSeries'' too.
** ''StarTrekForgedInFire'' ties Sulu's captaincy of the ''Excelsior'' (as seen in ''The Undiscovered Country'' and explored further in StarTrekTheLostEra) to the Blood Oath plot from the eponymous episode of ''Series/StarTrekDeepSpaceNine''. In other words, Sulu's story arc is now made part of the backstory of Curzon Dax and the Klingon trio of Kor, Kang and Koloth. The novel also ties in the Klingon Forehead arc, from ''Series/StarTrekEnterprise'' and StarTrekVanguard.
** The ''Literature/StarTrekTyphonPact'' novel ''Paths of Disharmony'' links the StarTrekVanguard story arc to those of the StarTrekDeepSpaceNineRelaunch and the post-StarTrekDestiny line, making it all relevant to the current events of the novel.
** A rather pleasing example in the ''Literature/StarTrekVoyagerRelaunch'' with the exploits of Kahless, retroactively linking the novel line's Klingon saga to the relaunch in interesting ways. In ''StarTrekATimeTo'', Kahless had replaced himself with a hologram (equipped with a mobile emitter) and wandered off to Cygnet IV, supposedly to "do whatever (he) felt like". It was also a test, allowing him to give his usual HurricaneOfAphorisms when the ruse was discovered. In the ''Literature/StarTrekVoyagerRelaunch'', though, it's revealed why he was on Cygnet IV specifically. [[spoiler: The secret headquarters of the qawHaq'hoch are located there, and he's keeping the plates spinning in the plan to keep Miral (B'Elanna and Tom's daughter) safe from the fanatics trying to kill her. Further, the mobile emitter for his holographic replacement was created by B'Elanna herself]].
** Any Christopher L. Bennett novel in the line (''Ex Machina'', ''The Buried Age'', ''Watching The Clock'') is like this. It sometimes borders on ContinuityLockout, but never crosses the line.
** The ''Q Continuum'' trilogy ties together three previously unconnected malevolent energy beings from the original series and movies along with the Galactic Barrier (yes, one of them is "God" from Star Trek V), and as an extension explains why proximity to the barrier resulted in the development of telekinetic powers and personality shift in the series pilot.
* After Creator/IsaacAsimov's extensive CanonWelding of his Foundation, Empire and Robots series into one, the final volume of the Second Foundation Trilogy, ''Foundation's Triumph'' by Creator/DavidBrin was a fantastic example of ArcWelding together almost every single book in the series together even better than Asimov had done.
* All 7 other of the ''IncarnationsOfImmortality'' series, encompassing epic acts by Death, Time, Fate, War, Nature, God and the Devil had this trope. In the latest novel in the series ''UnderAVelvetCloak'', all of these acts are only minor compared to Nox's (the Incarnation of Night/Secrets) actions (whose actions choose which universes live or die).
* Some ''Literature/WarriorCats'' books have melded two subplots together to make their story through use of a retcon.
** ''Crookedstar's Promise'' introduces the Dark Forest to the past and shows it influencing the events of book as early as ''Fire and Ice'' through use of Crookedstar's story.
** ''Yellowfang's Secret'' makes it so that [=SkyClan=] is directly responsible for the rise of Brokenstar, even though they had died out years before his birth.
* The Larry Niven KnownSpace stories develop a bad case of this later on, as the hugely successful RingWorld degenerated into increasingly complex and incomprehensible attempts to produce a Unified Field Theory Of Everything.
** Also the Arthur C Clarke Rama and related sort-of-sequels to 2001 - A Space Odyssey.
[[/folder]]

[[folder: Live Action TV ]]
* One of the more explicitly identified examples of ArcWelding comes from ''Series/{{Angel}}'''s fourth season, where Skip notes that everything that's happened to Angel and company for a very long time -- Angel's ensouling, Cordelia's ascension, Fred's being trapped in Pylea, Lorne's banishment ''from'' Pylea -- were all part of a GambitRoulette.
** A smaller version then happened in the next and final season: faced with ExecutiveMeddling to be more episodic without any arcs, after finding out the show would be canceled anyway Joss spent the last two episodes revealing that many of the villains over the season were part of a group called the Circle of the Black Thorn, then having the heroes kill them all.
* BurnNotice: Anson, Anson, Anson
* ''Franchise/StarTrek'': ''[[Series/StarTrekDeepSpaceNine Deep Space Nine]]'' does excellent examples of {{Story Arc}}s and also of ArcWelding. Starting in mid-season 2 and possibly earlier, the seeds are planted in an almost offhanded manner for the coming storyline. Then, at the end of season 2, it's all revealed to be part of a big plot that isn't concluded until the final episode of the final season -- which itself is the finale of a 9-part arc within the MythArc of the show.
** Also, ExecutiveMeddling resulted in the Klingons returning to their [[Series/StarTrekTheOriginalSeries Kirk-era]] level of villainy just as the Dominion was planned to take center stage. ThePowersThatBe did the best they could, and made it fit at the end by making Changeling manipulation responsible.
* ''Series/TheXFiles'' did this in later seasons, with dormant alien DNA supposedly accounting for much of the apparently Earthbound paranormal activity Mulder and Scully investigated.
* ''Series/{{Heroes}}'' was notoriously bad at Arc Welding especially during the "Villains" volume.
* Arc Patching, if not ArcWelding, was done in ''VeronicaMars'', when the season 2 bus bombing storyline wrapped up. The perpetrator was revealed to also have raped Veronica at Shelly Pomroy's party, a storyline thought to be wrapped up in season 1 as being not rape, but mutually drugged-up semi-consensual sex. This explained Veronica's chlamydia, despite her having only two (or, as TheReveal made plain, actually three) sexual partners and presumably using protection, the existence of which was used to paint Veronica as a slut and therefore untrustworthy in the trial of Aaron Echolls. The blatant illegality of delving into her medical records for some reason ''not'' resulting in a mistrial is another debate entirely.
* At the end of the first season of ''Series/TheSopranos'', Big Pussy has vanished. [[TitleDrop No one knows anything]]. The writers of the show were just going to let it go at that--people do, indeed, vanish with no explanation, though it's rare. However, when they heard how the fans were wondering what happened to him, they welded Pussy into the story of Jimmy's being TheMole, with him being a second one.
* ''Series/DoctorWho'':
** There was a bit of ArcWelding near the end of its original run, when Ace's involvement with the Doctor between "[[Recap/DoctorWhoS24E4Dragonfire Dragonfire]]" and "[[Recap/DoctorWhoS26E3TheCurseOfFenric The Curse of Fenric]]" (eight multi-part stories over three seasons by that point) was revealed to be part of Fenric's BatmanGambit to trap the Doctor (moral of the story: don't try a BatmanGambit against a {{Chessmaster}}). It also provided a [[HilariousInHindsight bit of disappointment]] for Classic Who fans when the series returned and [[ArcWords "Bad Wolf"]] turned out not to be a returned Fenric.
** Between the Classic and revival series, the Time War, a cataclysmic war between the Daleks and the Time Lords, annihilated both races for good with the exception of the Doctor. The series eventually connects this event to the Fourth Doctor story "Genesis of the Daleks", where the Doctor attempted a genocide of the species but failed (which has no serious effects on the Classic series's overarching plot save for [[HijackedByGanon introducing Davros]]) - reimagining the event as the Time Lords firing the first shot in the war.
** In [[Series/DoctorWho NuWho]] Series 5, the startling lack of historical commentary about a big freaking Cyberking stomping around Victorian London is retconned to have been another casualty of the cracks in time.
** "The Time of the Doctor", the Eleventh Doctor's era GrandFinale, concludes virtually all major ongoing plots (the cracks in time, the explosion of the TARDIS, the First Question, etc.) by tying them into the Ninth and Tenth Doctor Time War MythArc.
* ''Series/{{Stella|US}}'' used [[YouLookFamiliar one frequent actor]] to set up an arc for the series.
* Graem Bauer and the "Bluetooth Group" in ''Series/TwentyFour''. The cabal of influential businessmen in the fifth season ordering Christopher Henderson et al. to do their dirty jobs was initially planned to be a shadowy group whose true motives were never explained (and they had no connection whatsoever to Jack or his past). In the sixth season, the previously unnamed head of this group was revealed to "Graem Bauer", and it was explained that he was responsible for most of the government's shady activities going all the way back to the fourth season (when Walt Cummings tried to have Jack killed). Graem is then revealed to be TheManBehindTheMan, as his (and Jack's) father Philip shows up and murders him in his very first appearance.
** Season 7 does it ''again'', revealing the season's BigBad, Alan Wilson, to have been behind even the Bauers' involvement, and the ultimate authority over the Season 5 conspiracy, being head of a [[TheOmniscientCouncilOfVagueness powerful group]] that had been manipulating events for some time and remained at large at the end of the season. Then the storyline [[AbortedArc disappeared without a trace]].
* A great many of the episodes of the '90s series of ''Series/TheOuterLimits'' were retroactively revealed to take place in the same continuity. Unfortunately for continuity, several of those episodes are entirely contradictory.
* ''Franchise/PowerRangers'' had two major examples of this:
** ''Series/PowerRangersInSpace'' revealed that [[BigBad Dark Specter]] was behind everything that happened in the series to that point. Combining the narratives of all the previous seasons ([[Series/MightyMorphinPowerRangers Mighty Morphin]], [[Series/PowerRangersZeo Zeo]], [[Series/PowerRangersTurbo Turbo]], and In Space) into one greater arc.
** In ''Series/PowerRangersNinjaStorm'' it is revealed that each plot by the [[ContractualGenreBlindness contractually genre blind]] BigBad Lothor was actually part of a very GenreSavvy BatmanGambit.
* ''Series/{{Chuck}}'' welded arcs on top of arcs. About midway through the first season everything that happened up to that point was revealed to largely be the result of a CIA splinter group known as FULCRUM attempting to steal the Intersect. By late in Season 2, Chuck has begun to speculate that many one-shot villains earlier in the first season such as Laszlo were actually connected to the Intersect project and FULCRUM. The Season 2 finale reveals that Fulcrum was part of a larger organization called the Ring. The middle of Season 3 reveals that the Ring's direct involvement goes back much further, and that another one-shot villain from Season 2 was actually working for them. When Season 4 rolls around, you learn that yet another one-shot villain from Season 2 was actually working for new series big bad Volkoff Industries, and that the entire history of the Intersect project itself was directly connected to Volkoff himself. Finally in Season 5 you learn that rogue CIA agent Quinn was quite literally behind EVERYTHING--Fulcrum, the Ring, and Volkoff Industries--out of his desire to get revenge on Chuck for "stealing" the Intersect from him.
* ''Series/KaizokuSentaiGokaiger'' episode 40, which not only turns the Gokaigers' EarlyBirdCameo (a BigLippedAlligatorMoment during the ''[[Series/TensouSentaiGoseiger Goseiger]]''/''[[Series/SamuraiSentaiShinkenger Shinkenger]]'' ReunionShow) a canon event, but also ties into the team's quest of GottaCatchThemAll.
* ''Series/{{Whitechapel}}'' did this in its fourth season. Up until this point, the team had dealt with unrelated cases, but the fourth season not only introduces the existence of the supernatural, but posits that all the grisly crimes in Whitechapel are the work of a "provocateur" who goads all the murderers into committing their crimes.
* ''Series/AgentsOfSHIELD'': The first midseason finale, "The Bridge", reveals that [[NebulousEvilOrganization Centipede]] was the same group controlling Akela Amadour via ExplosiveLeash, and they're now using the same technology to control their {{Super Soldier}}s.
** Two episodes later, we find out that recurring, seemingly independent, villain [[CorruptCorporateExecutive Ian Quinn]] is actually working for The Clairvoyant, the mysterious BigBad behind Centipede.
** "Turn, Turn, Turn" ties the Centipede/Clairvoyant StoryArc back into the main Franchise/MarvelCinematicUniverse (specifically, ''Film/CaptainAmericaTheWinterSoldier''), by revealing that [[spoiler: the "Clairvoyant" is actually one of HYDRA's moles in SHIELD, and Project Centipede was just another tool towards their goal of [[TakeOverTheWorld ruling the world]].]]
* ''Series/{{Arrow}}'': The first episode of the second season features a group of copycat vigilantes, who among other things kill Starling City's mayor. The midseason finale reveals that they were organized by [[DarkMessiah Brother Blood]] [[spoiler: and [[TheManBehindTheMan Slade]]]], in order to give [[VillainWithGoodPublicity Blood]] the opening he needs to run for mayor.
** Each season also finds a way to tie together its Present Day and Island Flashback storylines:
*** Season 1 revealed that [[BigBad Malcolm Merlyn]] was responsible for the shipwreck that stranded Oliver on the island to begin with.
*** Season 2's storylines are connected by [[PsychoSerum Mirakuru]]. It was his search for it that led [[EvilutionaryBiologist Dr. Ivo]] to the island in the flashbacks, it's being used as part of Brother Blood's plans in the present, [[spoiler: and it's responsible for Slade's FaceHeelTurn in the flashbacks that leads to him being BigBad in the present]].
* ''Series/TheBlacklist'': "Berlin, Part 1" confirms what was implied throughout the series, that the Blacklist is just a cover for a bigger plan on [[VillainProtagonist Reddington's]] part. While some appear to have truly just been chosen randomly, most were either targeted as a means to help Red find information on [[HiddenVillain Berlin]], or were actively Berlin's agents.
[[/folder]]

[[folder:Multiple Media]]
* The first ''Franchise/{{Noob}}'' novel did this to some episodes of the webseries, making it part of of the [[FictionalVideoGame ''Horizon'']] storyline. When an episode of Season 1 needed to show a character doing FetchQuest (which happened three or four times out of twenty often stand-alone episodes) the QuestGiver always happened to be InTheHood and dressed in BlackCloak, something that could easily be normal for the game and/or due to NoBudget. The first novel, chronologically set after the first season, reaveals that [[spoiler: the black cloak is actually a trademark for a group that is after the DismantledMacGuffin central to the fiirst novel ; some of the pieces were used as decoration for random objects that they sometimes couldn't go get themselves without attracting attention, hence the fetch quests]].
[[/folder]]

[[folder:Music ]]
* One of the few examples (perhaps the only one, seeing as concept albums are nowhere near as common as normal albums) occurring in Music: Music/BetweenTheBuriedAndMe do this with their Parallax storyline when it's revealed that Prospect 2 was [[spoiler:the adult male that talked too much in "Lost Perfection", and that he was one of the three lovers of the woman in "Prequel to the Sequel".]]
[[/folder]]

[[folder:Tabletop Games]]
* Up until the Invasion block of ''MagicTheGathering'', the storylines of the sets before were mostly WorldBuilding the plane of Dominaria. Then came the story revision, the Weatherlight set, and the Tempest block, which set up an ongoing storyline over the next twelve or so sets that would drastically change the way the game told stories, as well as cobble together all the previous sets into a sort of long-term storyline, which the arc would then deal with. It all came to a head in the Invasion block with the BigBad and his cronies from the previous stories converging on Dominaria to overlay the artificial plane of Rath (introduced in the Tempest bllock) and give the Phyrexians (introduced back in Antiquities, the second-ever set) a new world to ravage.
** Also, the problems that were dealt with in the Time Spiral block were said to have done things which were major in other blocks, like making the Emperor insane, which convinced him to steal a baby kami, which resulted in the Kami War which made up the Kamigawa block.
** ArcWelding in the "plotted as TheReveal" format is present in the Mirrodin blocks. The first is apparently a weird, completely new world of metal and artifacts. The second block revisits the setting to reveal that Phyrexia, defeated in the Invasion block, has infected the plane and is taking it over.
* The {{Ravenloft}} D&D setting's creators retroactively Arc Welded its first six adventures together into the Grand Conjunction story arc, using a Vistani prophecy as solder.
* Arguably, the D&D settings {{Planescape}} and {{Spelljammer}}, both of which were specifically created to allow the numerous other settings of D&D to mix with each other.
[[/folder]]

[[folder: Video Games]]
* ''VideoGame/MassEffect3'' had to explain new Reaper motivations after Drew Karpyshyn's "Dark Energy" explanation was abandoned. Each expansion built on it, most notably the "Leviathan" DLC.
* ''VideoGame/MetalGearSolid'' was mostly self-contained, despite being a sequel to the MSX games ''VideoGame/MetalGear'' and ''VideoGame/MetalGear2SolidSnake''. ''VideoGame/MetalGearSolid2SonsOfLiberty'' introduced [[AncientConspiracy The Patriots]], whose operatives were largely responsible for the events in the series. ''VideoGame/MetalGearSolid3SnakeEater'''s place in the Patriots arc is [[spoiler: their origin story (as evident by the password Zero instructs Snake to use when he meets ADAM),]] but it's missed by many until ''VideoGame/MetalGearSolid4GunsOfThePatriots'' spells it out because the Patriots as they exist by the time ''Sons of Liberty'' takes place are [[AIIsACrapshoot very, very different]] than the organization used to be.
* In ''GuildWars Nightfall'', it's revealed that servants of Abaddon were responsible for driving the Charr into human lands in Tyria, leading to all the major background events of the ''Prophecies'' campaign; another servant led to the downfall of Shiro Tagachi, the BigBad of ''Factions''.
* The VideoGame/ChzoMythos tetralogy of games feature this; ''5 Days a Stranger'' was originally a stand-alone game, as was its distant sequel, but the later titles tie them together to form an encompassing story arc. Appropriately, the major threat of the first two games (and an important story character in the other two) is an insane killer referred to as 'The Welder' because of the mask he wears.
* "Evolution requires sacrifice." Spoken by [[spoiler:Lumine]] of ''VideoGame/MegaManX8'', and Serpent of ''VideoGame/MegaManZX''. This refers to the evolution of the [[RidiculouslyHumanRobots Reploids]] into something else...Granted, those two are in a future (and a world) that ''anything's'' possible with the Reploids (or technology in general). And then, in the VideoGameRemake (and possibly ContinuityReboot) ''VideoGame/MegaManMaverickHunterX'', Sigma begins spreading these beliefs himself. [[WhatCouldHaveBeen If the reboot series wasn't axed]], the developers could have elaborated on the concept even more.
** Meanwhile, in ''VideoGame/MegaManZero'', unlike the [[VideoGame/MegaManClassic two]] [[VideoGame/MegaManX series]] that preceded it, there is a different BigBad for the first two games. Then, that novelty just had to be shot down by ''Zero 3'', wherein ''that'' game's BigBad, Dr. Weil, can be easily marked responsible for the events of the previous two, legibly making him the BigBad for the '''entire''' ''Zero'' series.
** Wily claims to have orchestrated ''VideoGame/MegaManBattleNetwork 2'' at the end of ''Battle Network 3,'' making the first three games one saga about Wily's plots to destroy the Internet (really) culminating with the Alpha plan in ''3''.
* VideoGame/KingsQuest: Dahlia, Hagatha, Mannanan, and Lolotte all appeared to be generic evil wizards and wicked witches. But then, we hear that the BigBad in VideoGame/KingsQuestV is the "brother" of Hagatha and Mannanan and looking for revenge. Then VideoGame/KingsQuestVI has a single, damning letter alluding to the "Brotherhood of the [[LegionOfDoom Black]] [[TheOrder Cloak]]," who address one another as "brother" and "sister." The letter implicates ''at least three'' of the series villains as members... and could possibly implicate ''all of them'' as members. OhCrap {{Fanon}}, especially the FanSequel and FanRemake games will ''cheerfully'' run with this theory.
* ''VisualNovel/AceAttorneyInvestigations 1 and 2'': [[spoiler: The first four seemingly unrelated cases turn out to have all been part of the BigBad's BatmanGambit. In fact, the main point of the final case is for the player to figure it out. It is, however, subtly foreshadowed from the beginning, and the hints are there if you look for them.]]
* For almost 20 years, ''[[VideoGame/SonicTheHedgehogCD Sonic CD]]'' was a GaidenGame with no set place in the series' timeline (Due to the lack of Tails or Super Sonic and the fact it was meant to be ''[[VideoGame/SonicTheHedgehog2 Sonic 2]]'', most fans just assumed it was a prequel). However, as of the new remake for X-Box Live, Playstation Network, and iPhones, features were added suggesting (and WordOfGod asserted) that it actually occurred sometime before ''[[VideoGame/SonicTheHedgehog4 Sonic 4]]'', and it will be specifically tied to Episode II.
* The four DownloadableContent packs of ''Videogame/FalloutNewVegas'' are part of a bigger storyline which lead to the confrontation of the player-character, The Courier with Ulysses, TheRival.
* In the second ''VideoGame/SuperRobotWarsOriginalGeneration'' game, the BigBad reveals that he was the driving force behind everything that happened so far in this continuity, even though the enemies faced so far had been completely separate threats before this point. The fandom quickly made a meme out of having him claim responsibility for just about anything.
** Other games in the [[VideoGame/SuperRobotWars series as a whole]] often do this, drawing on similarities between various different series to weave common bonds.
** VideoGame/SuperRobotWarsUX
*** By the way, [[MazinkaiserSKL the island covered by the gravity curtain was apparently a research center]] for gravity engine cores since World War II (a key plot point to ''The Wings of Rean'').
*** Linebarrel is connected to Demonbane because the latter is also a "[[AMechByAnyOtherName Machina]]" and the [[LinebarrelsOfIron Katou Organization]] are hunting them down. More specifically, Linebarrel and Demonbane are known as "Deus Ex Machina". Both stories' time loop events are interconnected in ''UX''.
*** Tatsumiya Island is a part of [[Anime/MobileSuitGundamSEEDDestiny ORB]].
*** Considering the whole Machina idea or rather the meaning behind it is machine god. Linebarrel's Juda seems central to the whole idea of gathering Demonbane, SD Gundam, Machina, Fei-Yen HD and even partially Heroman as a collection of possible Machinas, though obviously not all of them have the idea of a Machina god behind them or rather behind their respective series like Linebarrel and Demonbane do. This would be a reason for Juda and a way to tie in a lot of the story together.
*** Scenario 24 is a mash of the starting battle from ''Sayonara no Tsubassa'' as well as the titular impact of Trailblazer, by mixing in the fact that the Galaxy refugee ships were at Jupiter. Fighting Vajra ships for the first time is only a tease to the real first appearance of the ELS. This also gives the chance for more interactions between Alto and Setsuna, and the final save coming from Tieria in the Raphael.
*** Fei-Yen's plot is tied in with Mazinkaiser SKL, where it is the robot used by the female kingdom. She starts out really reserved, then once you go on SKL/Macross route split she has an encounter with Miku[[labelnote:*]]Note that in game she never mention Miku's name[[/labelnote]] and gets her KYUNKYUN beam, then during SKL finale she goes super mode[[labelnote:*]]which is basically Fei-Yen's original SuperMode[[/labelnote]] when Kiba shows up, and during Fafner TV finale, she gets her Morale boosting special command. [[spoiler:''In the Blue Sky'' and ''Operation Azure''. Sink it for a moment.]]
*** The Tokyo in the interior of the moon, which is from where all the Humanoid Machinas stem from, is also strikingly similar to Shou's Tokyo. Shou and the Dunbine characters are [[spoiler:basically from a previous incarnation of the world]]. [[spoiler:Later on we find out Juda's "view of future" are actually about what happened ''before'', so at least part of the cast are also of the same origin.]]
* ''VideoGame/PokemonMysteryDungeonExplorers'' had few [[StoryArc story arcs]] in the first place, but near the end of the game, you find out that [[spoiler: Darkrai was responsible for both [[MadGod Primal Dialga]] and Palkia trying to [[FateWorseThanDeath remove you from time and space respectively.]]]]
* ''VideoGame/StarTrekOnline'' has a number of Arc Welding as it takes everything it can from the TV series, movies, and other sources. Among those:
** Miral Paris' role as the Klingon Messiah is tied into how the Klingons regain their ridged foreheads between the original series and ''Film/StarTrekTheMotionPicture''.
** Near the end of ''Series/StarTrekDeepSpaceNine'', a group of Dominion ships is threatening to invade the titular [=DS9=] by way of the Bajorian wormhole when suddenly they just disappear! [[spoiler:They return in the Featured Episode series "The 2800"]].
** Probably the biggest one? The game's true BigBad? [[spoiler: The ''Iconians'', a group of not-so-extinct race that had ruled the galaxy thousands of years ago whose technology had been a real thorn in Picard and Sisko's sides when they encountered them in ''Series/StarTrekTheNextGeneration'' and ''Series/StarTrekDeepSpaceNine''. Even worse, it's ''them'' who had helped caused the destruction of Romulus and Remus in the backstory to ''Film/StarTrek2009''!]]
[[/folder]]

[[folder:Visual Novels]]
* Despite ''Visualnovel/NineHoursNinePersonsNineDoors'' feeling like a self contained story, it's sequel ''Visualnovel/VirtuesLastReward'' manages to very successfully connect it to that games myth arc (and by extension the overall plot of the eventual trilogy) by revealing that [[spoiler:Gentarou Hongou, aka Ace, was a member of Free the Soul, and that Cradle Pharmaceutical and his experiments with the morphogenetic field were funded by the cult. The symbol on the robes Snake was forced to wear in 999 is also used as Free the Soul's coat of arms.]]
[[/folder]]

[[folder:Webcomics]]
* ''Webcomic/ItsWalky''[=/=]''Roomies''[=/=]''Joyce and Walky''. The entire storyline consists of retconning arcs to weld them into bigger arcs reaching further into the past, culminating in a gigantic "conclusion" arc connecting every character that ever apeared in the comic into a huge overarching plot (whose final resolution ends the comic).
* ''Webcomic/DominicDeegan'': It turns out [[spoiler: the King of Callan, who wants humanity/himself to control the source of magic (which is apparently a comet) so badly he tried to ''destroy an entire country and wipe out its people'' when it was their "turn" use it]] was responsible for just about every catastrophe in the comic.
[[/folder]]

[[folder: Western Animation ]]
* Interviews with the creative team behind ''JusticeLeagueUnlimited'' and their remarks in various DVD audio commentaries reveal that they were several episodes into the production of ''Unlimited'' before they realized that they were working toward what became the "Cadmus Arc." The majority of the arc expanded upon and revolved around the events of "A Better World," an episode from season two of ''JusticeLeague'' which had been written with no thought to an ongoing story. The ultimate reveal of the BigBad, Brainiac, actually connected back to an episode of ''WesternAnimation/SupermanTheAnimatedSeries'', which had been produced eight years and two TV series before the current series was even conceived. There were also throw-away lines and references that connected to as far back as "On Leather Wings," an episode of ''WesternAnimation/BatmanTheAnimatedSeries'' that was the ''very first'' entry in the {{DCAU}}.
* Parodied in ''WesternAnimation/CloneHigh'''s final episode, where the [[TheOmniscientCouncilOfVagueness Shadowy Board of Directors]] bring together literally every one-shot guest character or celebrity and address them as collaborators. Of course, this was mostly just so the episode could end with [[spoiler:''literally every character ever to appear on the show'' - except Scudworth - frozen inside a meat locker.]]
* Most of the middle part of ''WesternAnimation/{{Gargoyles}}'' season 2 was already an arc, but then, during the two-part episode "The Gathering", where you see Oberon's Children filing into his castle to be recognized by him back on Avalon--and you realize they're familiar to you. Odin, Anansi, Banshee, Coyote, even Anubis are all his subjects. How powerful, then, must Oberon be? This was already a StoryArc of sorts--though Angela's, Goliath's, and Elisa's adventures were episodic, they were already linked by their method of travel--but now you see it was all part of a second arc as well, to set up the StoryArc finale.
** Also, many unrelated aspects of the first half of the series were ultimately revealed as part of [[EvilSorcerer the Archmage's]] far-reaching BatmanGambit for world domination.
* ''WesternAnimation/TransformersAnimated'' had Ratchet's war flashbacks; in "Thrill of the Hunt" he flashes back to serving alongside Arcee, and in "A Bridge Too Close" he recalls having served in the war with Omega Supreme, [[spoiler:also the Autobots' ship]], as an old friend. The third season reveals that [[spoiler:Arcee's role as intelligence officer during the war had actually been to carry the activation codes necessary to implement Omega Supreme, an experimental weapon.]]
* This happens with ''WesternAnimation/CodenameKidsNextDoor'' in its first season. It turns out that Father was behind a lot of the episodes.
* ''StrokerAndHoop'' finale has them kidnapped along with Double Wide and put inside K.A.R.R over a canyon while being taunted by their kidnapper who gives them three guesses on who he is lest he drops them in the canyon. Through the whole episode the three call back recent episodes and go over suspects. [[spoiler: Its eventually revealed to be a no name background character whose appearance changed in each encounter with the duo save for his voice.]]
* The ''WesternAnimation/{{Futurama}}'' episode "The Why of Fry" reveals that Fry coming to the future was part of a wider conspiracy, as his lack of delta brain wave made him the only person who could save the Universe from the Brainspawn. Whilst at least part of this was planned from the beginning of the show, the events of "Roswell That Ends Well" (where Fry becomes his own grandfather) were used as an explanation for the lack of brain wave, which was not part of the original plan.
* The ''WesternAnimation/SouthPark'' episodes "200" and "201" begin as a follow-up to "Trapped in the Closet" and then tie together the plots in "Mecha-Streisand," "Ginger Kids," "Scott Tenorman Must Die," "The Super Best Friends," "Butt Out," "Fat Butt and Pancake Head," the "Cartoon Wars" two-parter, and "Cartman's Mom Is Still a Dirty Slut," and this does not include the numerous previously one-shot characters who make another appearance in this two-parter.
* Various jokes and gags made in the purely episodic first season of ''WesterAnimation/AdventureTime either return in later seasons to help reveal new plot information, or are expanded upon to bring more insight into a character. A major example includes the episode "I Remember You", which uses an early throwaway gag of Marceline constantly moving all over the Land of Ooo, and explains the main reason for this being an escape from [[spoiler: her now mentally-insane father figure, the Ice King, who took care of her during the nuclear apocalypse]].
[[/folder]]

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