History Main / IntercontinuityCrossover

[[folder: Theme Parks]]
* Several examples in the Ride/DisneyThemeParks. The biggest example is ''{{Fantasmic}}'', where a LegionOfDoom of Disney Villains [[BattleInTheCenterOfTheMind invade Mickey's mind]].

* The first Creator/VertigoComics Winter's Edge special has a ''House of Secrets'' framing story where Rain visits an art gallery in the house that shows her stories from ''ComicBook/TheSandman'', ''BooksOfMagic'', ''ComicBook/{{Hellblazer}}'', ''The Dreaming'', ''The Minx'', ''Nevada'' and ''ComicBook/TheInvisibles''. While the first four are part of one continuity, the latter three are all individual continuities, as is ''House of Secrets'' itself.

----

For more information and examples, see [[http://www.poobala.com/crossoverlist.html Thom Holbrook's Crossovers and Spin Offs Master List]], which documents all known crossovers between TV series, except for cartoons. With this information, the site has been able to identify no fewer than 38 contiguous TV "universes" (as of March 2008) which are home to widely disparate (and apparently unlikely) combinations of series from different eras and networks. For instance, see Holbrook's [[http://www.poobala.com/crossoverlistb.html#G2 "Group 2"]] -- ''ninety-four'' series (as of March 2012) ranging from ''Series/SixFeetUnder'' and ''Series/EverybodyLovesRaymond'' to ''Series/LawAndOrder'' and ''Series/TheXFiles'', taking in ''Series/{{Mash}}, Series/CopRock'', and ''Series/HomeImprovement'' along the way. Thanks to the baroque web of interconnections and crossovers, it is suggested that these shows all inhabit the same universe. (Holbrook also discovered the "JeanClaudeVanDamme is dead" plague that poses a grave threat to any future crossovers including ''Star Trek'' and other Group 10 shows.)

** ''Fairy Tail'' also had a crossover with the story Mashima wrote before it, ''RaveMaster''. The Jiggle Butt gang appeared in the anime as well.

** This was because the anime adaptations of both series were produced by TMSEntertainment.

** An unfortunate side-effect of this is that the closest Jubilee has ever come to a serious relationship is with [[RobinSeries a guy who lives in another universe]].
* Some comics by Roy Thomas saw a team-up between Creator/RobertEHoward's ''Franchise/{{Conan|TheBarbarian}}'' and Creator/MichaelMoorcock's ''[[Literature/TheElricSaga Elric of Melnibone]]''.
** On Elric's side this makes sense, as his home continuity is explicitly one of many parallel worlds.

** And in ''ComicBook/TwoThousandAD'' publications themselves, Dredd has crossed paths with Johnny Alpha from ''StrontiumDog'' twice (Both of these strips have been created by the same people) and has seen a whole score of cameos from outside characters during the ''Helter Skelter'' story arc.

* Illyria of the ''Buffy Verse'' has appeared in PeterDavid's ''Fallen Angel''. David also wrote an earlier Illyria-one-shot.

* The online FanFilm ''WebAnimation/{{Haloid}}'', a truly impressive ''Franchise/{{Halo}}''/''Franchise/{{Metroid}}'' crossover. Technically, also a [[spoiler: ''VideoGame/DeadOrAlive'']] crossover.
** The ongoing crossover series by the same author called ''WebAnimation/DeadFantasy'', consists primarily of stunt-laden over-the-top battles between characters from ''VideoGame/DeadOrAlive'', ''Franchise/FinalFantasy'', ''VideoGame/NinjaGaiden'', and ''Franchise/KingdomHearts''.

** In fact, due to the popularity of Friendship is Magic, and very prolific fanfic writers, My Little Pony: Friendship is Magic has crossed over with just about everything, from DresdenFiles to ''Series/StargateSG1''.

* [[FanFic/ConnectingTheDots "Connecting the Dots."]], an intercontinuity crossover between the {{Justice League|OfAmerica}} and Manga/{{Naruto}}, along with a few thousand random cultural references. Think Superman fighting Naruto.

* ''{{Series/Animorphs}}'' is another series that's something of a crossover magnet because it's very easy to work in people who are controllers. It's been crossed with ''Series/{{CSI}}'', and ''MaximumRide'' is a frequent crossover because of similarities between The Flock and Tobias. ''Series/BuffyTheVampireSlayer'' and ''Series/{{Roswell}}'' were both crossed with it despite both shows being referenced as fiction in the books.

** The ''Series/DoctorWho''/''EastEnders'' crossover (of very dubious quality, but it was for charity) ''Dimensions in Time'' could also be mentioned, although it's [[FakeCrossover actually not in either of the shows' continuities]] (and indeed, since then they've [[MutuallyFictional both featured each other as fictional programmes]]).

* It appears that the soap opera ''{{Passions}}'' has set itself up as a sequel of sorts to the classic FantasticComedy ''Series/{{Bewitched}}''. It features Juliet Mills as Tabitha Lennox, a genuine witch whose daughter is named Endora and whose parents are a mortal named Darrin and a witch named Samantha. Furthermore, Bernard Fox has made two appearances on the show as his ''Bewitched'' character, Dr. Bombay.

** On the other side of the Pacific, the world of the ''Series/SamuraiSentaiShinkenger'' had an unexpected visitor in ''KamenRiderDecade''. The crossover is in continuity for both shows; in fact, the fact that the ''Shinkenger'' world is the only world in ''Decade'' that is the genuine, canonical universe of the show in question rather than an AlternateUniverse (original worlds aside) is a plot point for the arc. [[note]]Speaking of which, ''Franchise/PowerRangers'' already beat ''Franchise/SuperSentai'' at a ''KamenRider'' crossover long ago with ''Series/MightyMorphinPowerRangers''' PoorlyDisguisedPilot for ''Series/MaskedRider''.[[/note]]

*** Not as much as you might think : The actual ''[=DvD=]'' show ended with Rob Petrie trying to find a buyer for his life story, and Alan Brady hinting that he might want to turn it into a show, which is so meta it hurts. So, it's possible that, in the fictional world where Rob, Laura, and Alan Brady live or lived alongside the ''Mad'' and ''Friends'' characters, Alan Brady eventually settled on Dick Van Dyke to play Rob Petrie -- brain exploding must stop...
** Also, Chandler briefly appeared in a ''CarolineInTheCity'' episode, and Caroline briefly appeared in a ''Friends'' episode.

* ''Series/CrossingJordan'' and ''Series/LasVegas'' crossed over so often that it probably doesn't even qualify as intercontinuity crossover. They certainly take place far enough apart geographically that it's plausible that they're within the same continuity. I think that the ''CrossingJordan'' characters made one more appearance in ''Series/LasVegas'' after their own show had been canceled, though both shows are now finished.

** Later episodes would have Batman and Robin meet Colonel Klink from ''HogansHeroes'' or Lurch from ''TheAddamsFamily.'' in the window gag.
* USANetwork does this on a regular basis in their ads. If you take, say, [[http://www.youtube.com/watch?v=R8oW0wBWlog "Monk: A Tribute"]] as canon, ''Series/{{Monk}}, Series/{{Psych}}, Series/RoyalPains, Series/LawAndOrderCriminalIntent, Series/InPlainSight,'' and ''Series/BurnNotice'' all take place in one universe. Sooner or later, all of their major series end up there.

* RLeeErmey turned up in Season 1 Episode 4 of ''Series/PawnStars'' in full ''Lock n' Load'' gear.
* ''Series/AllyMcBeal'' and ''ThePractice'' had a two-part crossover special that started on ''Series/AllyMcBeal'' on Fox and was resolved in the next hour on ''ThePractice'' on ABC, with several characters from each show appearing on the other show. Both shows were produced by David E. Kelley.

** One between ''TheCatherineTateShow'' and ''Series/DoctorWho'' (with a bit of RecursiveCanon).

* Similarly, 2010's ChildrenInNeed telethon included ''{{East|Enders}} [[Series/CoronationStreet Street]]'', in which a bunch of characters from each soap arrive at the location of the other one, including Gail Platt and Denise Johnson competing to see who has the most tragic backstory. The cliffhanger ending was that Liz Macdonald is [[LukeIAmYourFather Kat Moon's mother]], in a direct parody of the revelation that Kat is Zoe's mother. See also the ''Series/DoctorWho'' entry above for an earlier ChildrenInNeed '''Stenders'' crossover.
* BryanFuller likes to do this. Marianne Marie Beetle was a tenant of Jaye's trailer park in ''Series/{{Wonderfalls}}'', and then showed up at a competition in ''Series/PushingDaisies'', despite the fact that Jaye's brother in ''Wonderfalls'' plays the main character, Ned, in ''Pushing Daisies'', so they exist in the same universe, technically. And Jaye's mother is also Mother Superior in the second season of ''Pushing Daisies''.

* When Wrestling/HulkHogan's first movie, ''Film/NoHoldsBarred'', hit theaters, the Wrestling/{{WW|E}}F thought it'd be a good idea to bring in the villain of the film, [[http://www.thewrestlinglegendsforum.com/wrestlecrap/zeus.html Zeus]], to battle Hulk in a WWF ring. They were never really clear on whether this was supposed to be the movie character come to life, or the actor assuming the character's persona to wreak havoc (in some promos, he'd lean one way, in others, the other), but one thing was absolutely clear throughout the entire angle: it was Website/{{WrestleCrap}}.
* Franchise/{{Robocop}} (yes, [=RoboCop=]!) appeared at Wrestling/{{WCW}}'s ''Capital Combat 1990'' to rescue Wrestling/{{Sting}} from a cage he was placed in by the Four Horsemen.

* Several examples in the DisneyThemeParks. The biggest example is ''{{Fantasmic}}'', where a LegionOfDoom of Disney Villains [[BattleInTheCenterOfTheMind invade Mickey's mind]].

** And also ''G.I. Joe'' action figures for ''VideoGame/StreetFighterII''. In fact, it was there when Ken got his last name, Masters, because they couldn't name an action figure "Ken" thanks to ''{{Barbie}}''.

* ''VideoGame/GarrysMod'' allows you to do all kinds of crossovers with the right mods. Want [[VideoGame/{{Halo}} John-117]] to team up with [[VideoGame/{{Half-Life}} Gordon Freeman]] and fight [[Franchise/MassEffect Saren]]? Have fun.

* ''VideoGame/SuperSmashBros'' which features ''all'' of the first- and second-paty Nintendo characters meeting (though technically it's not them, they're just Gashapon figurines brought to life). From Mario, to Link, to the Pokemon. And now there's the ones not from Nintendo, such as {{Franchise/Sonic|TheHedgehog}} and [[Franchise/MetalGear Snake]].

** Also notable in ''Super Robot Wars OG Saga: EndlessFrontier'', Reji and Xiaomu from ''VideoGame/NamcoXCapcom'' confirm that KOS-MOS from ''VideoGame/{{Xenosaga}}'' comes from their future (which was already established in the former's game).

* ''VideoGame/RealityOnTheNorm'', a SharedUniverse RoundRobin series, has had some games about character from other games enetering the city of Reality, such as VideoGame/CommanderKeen or Monty Mole. Then there's ''Shadows of RON'', whose developer actually included the character from his own book series as the protagonist.

* ''WebAnimation/DeadFantasy'', a {{Machinima}} series which pits ''VideoGame/DeadOrAlive'' heroines and ''Franchise/FinalFantasy'' heroines against each other. And it is ''glorious''.
* CodeMent and NonePiece cross over in episode 14.5/6. It's even more incoherent than usual.

** The episode name, for the curious, is ''The Green Loontern''. And in another episode (''Samurai Quack'') Dodgers takes the place of WesternAnimation/SamuraiJack. Complete with [[strike:Aku]] Achoo, voiced by Mako himself.
* On ''WesternAnimation/TheSimpsons,'' Homer's claim to having had a close encounter with an extraterrestrial is investigated by none other than [[Series/TheXFiles Agents Scully and Mulder]].
** [[http://media.screened.com/uploads/0/5735/318691-thesimpsons_super.jpg The Agents asked if any of the following aliens are familiar]]: [[WesternAnimation/LooneyTunes Marvin the Martian]], Series/{{Alf}}, [[Franchise/StarWars Chewbacca]], and [[Film/TheDayTheEarthStoodStill1951 Gort]].
*** Writer Mike Reiss described it as the "most illegal shot" in the show's history.

----

** In fact, due to the popularity of Friendship is Magic, and very prolific fanfic writers, My Little Pony: Friendship is Magic has crossed over with just about everything, from DresdenFiles to StargateSG1.

** On the other side of the Pacific, the world of the ''Series/SamuraiSentaiShinkenger'' had an unexpected visitor in ''KamenRiderDecade''. The crossover is in continuity for both shows; in fact, the fact that the ''Shinkenger'' world is the only world in ''Decade'' that is the genuine, canonical universe of the show in question rather than an AlternateUniverse (original worlds aside) is a plot point for the arc. [[hottip:* :Speaking of which, ''Franchise/PowerRangers'' already beat ''Franchise/SuperSentai'' at a ''KamenRider'' crossover long ago with ''Series/MightyMorphinPowerRangers''' PoorlyDisguisedPilot for ''Series/MaskedRider''.]]

* When it was originally planned as a four-issue limited series, ''Franchise/{{Transformers}}'' shared the same 616 universe as other Marvel characters. J. Jonah Jameson sent Peter Parker to Oregon to investigate the Transformers ([[MemeticMutation he wanted pictures of Optimus Prime]]) and thus Spidey and the Autobots teamed up. When the title became a monthly ongoing series, however, the crossover was [[CanonDiscontinuity quietly forgotten]]. The ''Franchise/{{Transformers}}'' letter column even asked fans to please ignore the earlier Marvel crossover stories.

* ''ComicBook/HackSlash'' has crossed over with several other horror series and characters, including Evil Ernie from ''LadyDeath'', ''Film/ChildsPlay'', ''Film/{{Hatchet}}'', {{BUMP}}, and ''Film/{{Re-Animator}}''. Tim Seeley, the writer, has said in interviews that he considers '''all''' slasher films to take place in the same universe of canon (justified by some of the entries in the cinema section of this page).

* ''Comicbook/CaptainAtom: Armageddon'' thrusts the DC Comics hero into Jim Lee's Creator/{{Wildstorm}} universe. The mini-series functions as a CosmicRetcon for {{Wildstorm}}, and allows those comic readers who generally hated the ridiculousness of ''Comicbook/TheAuthority'' watch them get their heads handed to them.

* The online FanFilm ''WebAnimation/{{Haloid}}'', a truly impressive ''Franchise/{{Halo}}''/''VideoGame/{{Metroid}}'' crossover. Technically, also a [[spoiler: ''VideoGame/DeadOrAlive'']] crossover.

* ''{{Series/Animorphs}}'' is another series that's something of a crossover magnet because it's very easy to work in people who are controllers. It's been crossed with ''Series/{{CSI}}'', and ''MaximumRide'' is a frequent crossover because of similarities between The Flock and Tobias. ''Series/BuffyTheVampireSlayer'' and ''{{Roswell}}'' were both crossed with it despite both shows being referenced as fiction in the books.

** And in ''VideoGame/MortalKombat9'' DLC, vs [[Franchise/ANightmareOnElmStreet Freddy Krueger]].
** The {{P|layStation3}}S3 version of Mortal Kombat 9 had Kratos from ''VideoGame/GodOfWar'' as a GuestFighter.

* This has become a recent trend with ShounenJump manga, and the anime adapted from them.
** ''{{Gintama}}'' and ''SketDance'' had a crossover chapter for each manga, and two corresponding crossover episodes.
** {{Toriko}} and OnePiece had two crossover episodes (one of which was adapted from a manga crossover).
** And, most recently, ''OnePiece, ''{{Toriko}}'', and ''DragonBallZ'' had a crossover episode, though it obviously had no bearing on the continuity of any of the anime involved.

* ''Comicbook/CaptainAtom: Armageddon'' thrusts the DC Comics hero into Jim Lee's {{Wildstorm}} universe. The mini-series functions as a CosmicRetcon for {{Wildstorm}}, and allows those comic readers who generally hated the ridiculousness of ''Comicbook/TheAuthority'' watch them get their heads handed to them.

** A recent company crossover between IDW and Marvel did have the Avengers and Autobots team up. It's considered ambiguously canon by IDW.

** In a similar vein, ''Comicbook/TheAvengers'' once appeared on ''[[DavidLetterman Late Night With David Letterman]]''.

* The six issue [[JusticeLeagueOfAmerica JLA]]/''ComicBook/{{The 99}}'' miniseries.

* ''Series/{{Star Trek|TheOriginalSeries}}''[=/=]''Comicbook/{{Legion of Super-Heroes}}'', from {{IDW|Comics}} and Creator/DCComics. Interestingly transplants both sets of characters to a ''third'' universe; a [[FusionFic Legion-flavoured version]] of the MirrorUniverse where the Imperial Planets' Starfleet wears both the Sword-and-Earth crest and the Science Police badge, and the resident {{Proud Scholar Race|Guy}} have pointy ears and arched eyebrows ''and'' green skin and blond hair. Oh, and TheEmperor of TheEmpire? [[MagnificentBastard Vandal]] ''fucking'' [[TheConstant Savage]] (Or is it an evil Flint?)!

* ''CrossingJordan'' and ''Series/LasVegas'' crossed over so often that it probably doesn't even qualify as intercontinuity crossover. They certainly take place far enough apart geographically that it's plausible that they're within the same continuity. I think that the ''CrossingJordan'' characters made one more appearance in ''Series/LasVegas'' after their own show had been canceled, though both shows are now finished.

* ''PicketFences'' crossed over into ''Series/ChicagoHope'' (both shows created/executive produced/written by David E. Kelly and airing on CBS), when Fyvish Finkel's character Douglas Wambaugh checked into the hospital. They also poked at ''Series/{{ER}}'' featuring a "commercial" for the hospital that parodied the opening credits of ''ER'' and later having one character say, "We don't like to talk about that ''other'' hospital."

** The franchise also crossed over with ''ColdCase'' and ''WithoutATrace'' one time each. Some consider those two plus the three CSI series to be one big 'verse.

*** Actually, this is an example of a SharedUniverse, as both shows (as well as Series/{{Alphas}}) are part of the "SyFy Verse".

* [[Series/{{ER}} Susan's]] niece was missing when her sister Chloe overdosed, and was found by [[ThirdWatch the police in New York]].

* Similarly, 2010's ChildrenInNeed telethon included ''{{East|Enders}} [[CoronationStreet Street]]'', in which a bunch of characters from each soap arrive at the location of the other one, including Gail Platt and Denise Johnson competing to see who has the most tragic backstory. The cliffhanger ending was that Liz Macdonald is [[LukeIAmYourFather Kat Moon's mother]], in a direct parody of the revelation that Kat is Zoe's mother. See also the ''Series/DoctorWho'' entry above for an earlier ChildrenInNeed '''Stenders'' crossover.

* The NickVerse includes several DanSchneider productions like ''{{Zoey101}}'', ''{{iCarly}}'', ''{{Victorious}}'', ''SamAndCat'' and ''DrakeAndJosh'' as the core of the SharedUniverse. However:
** It ''also'' includes SketchComedy shows ''AllThat'' and ''TheAmandaShow''.
** It '''also''' includes ''YoGabbaGabba'' which had crossovers with ''BigTimeRush'' and ''TrueJacksonVP''.
** Carlton Banks from ''TheFreshPrinceOfBelAir'' shows up in an episode of ''BigTimeRush'', which puts the entire NickVerse into the StElsewhere "It Was All A Dream" continuity.

* Several examples in the DisneyThemeParks. The biggest example is ''{{Fantasmic}}'', where a LegionOfDoom of Characters/DisneyVillains [[BattleInTheCenterOfTheMind invade Mickey's mind]].

** Likewise with ''Webcomic/GrimTalesFromDownBelow'' which has even more crossover such as ''GrimAdventuresOfBillyAndMandy'', ''DannyPhantom'', ''TheNightmareBeforeChristmas'', ''{{Spawn}}'', etc. Yes Bleedman just really likes doing these.

* This one's a little older, but in an episode of ''Radio/TheJackBennyProgram'', Jack goes to court for supposedly murdering a rooster he owns. Who does he get as his lawyer? PerryMason. Although it may not count officially, since it was AllJustADream on Jack's part. Oh, and the true murderer? [[spoiler: Perry Mason himself]].

** It '''also''' includes ''YoGabbaGabba'' which had {{Crossovers}} with ''BigTimeRush'' and ''TrueJacksonVP''.

* [[WebVideo/DragonBallAbridged Ghost Nappa]] has been in a [[WebVideo/YuGiOhTheAbridgedSeries duel]], [[VisionOfEscaflowneAbridged Atlantis]] and Creator/{{Lanipator}} and Kaiser Neko's hotel room.

** [[Radio/{{Dragnet}} "Gee, Joe. You haven't been the same since your son went crazy in Vietnam"]]

* Franchise/{{Godzilla}} once did battle with {{SHIELD}}, the ''Comicbook/FantasticFour'', ''Comicbook/TheAvengers'', ''Comicbook/IronMan'', and various other {{Creator/Marvel|Comics}} characters. And yes, [[CrowningMomentOfAwesome it's EVERY bit as cool as it sounds.]]

* ''Series/{{Fringe}}'' has a particularly interesting example of this trope. The Observer, or rather [[spoiler: one of them, specifically September]], whose task it is to police inter-dimensional travel and interferences with the timeline, has managed to crossover from the ''Fringe'' continuity... into the "real world". He appeared in the audience of ''AmericanIdol'' and has been spotted in various stadiums during Fox sports broadcasts.

* ''VideoGame/RealityOnTheNorm'', a SharedUniverse RoundRobin series, has had some games about character from other games enetering the city of Reality, such as CommanderKeen or Monty Mole. Then there's ''Shadows of RON'', whose developer actually included the character from his own book series as the protagonist.

[[caption-width-right:307: And [[HilariousInHindsight now that they're owned by]] the same [[Creator/{{Disney}} company]]...]]

->'''Jigsaw:''' [[HannibalLecture You wallow in hypocrisy, Angus]]. [[TheReasonYouSuckSpeech Your life has been dedicated to nonviolence, which you advance by jerry-rigged poisons and explosives, pretending that using one form of violence over another makes you better than others]]... Well, now it is time to see how far you're -- did you just turn your manacles into laser beams?\\

But what happens when [[TheViewAskewniverse Jay and Silent Bob]] turn up in ''Film/{{Scream 3}}''? Or Cliff and Norm from ''Series/{{Cheers}}'' book into ''Series/StElsewhere'' for medical attention? Or a police officer from the grittily realistic ''Series/HomicideLifeOnTheStreet'' arrests Fox Mulder of ''Series/TheXFiles''? Or the CSI team finds a corpse in a hotel that isn't a corpse, just Series/{{Angel}}? Well, then you've got yourself a different kettle of fish altogether. And to add insult to injury, the fish are probably from ''WesternAnimation/FindingNemo'' and ''Disney/TheLittleMermaid''.

** And now ''Series/{{Hannibal}}'' is part of the continuity. Gretchen Speck (she dropped the Horowitz in the divorce, apparently), from Wonderfalls, is in Hannibal, and played by the same actress. (And in BryanFuller fashion, CelebrityParadox kicks in, because Caroline Dhavernas is in both.)

->'''Jigsaw:''' [[HannibalLecture You wallow in hypocrisy, Angus]]. [[TheReasonYouSuckSpeech Your life has been dedicated to nonviolence, which you advance by jury-rigged poisons and explosives, pretending that using one form of violence over another makes you better than others]]... Well, now it is time to see how far you're -- did you just turn your manacles into laser beams?\\

* NewJapanProWrestling has Jushin Liger, Tiger Mask, and Black Tiger, all of whom were anime characters before NJPW licensed their likenesses and created wrestlers out of them. It makes sense for Tiger Mask and Black Tiger, as the anime they originate from was about wrestling in the first place, but Jushin Liger was created for a {{Henshin}} series that takes place TwentyMinutesIntoTheFuture about a holy warrior with the power of the liger (half-lion, half-tiger) who battles evil aliens bent on destroying the world. Makes sense.
* When Wrestling/HulkHogan's first movie, ''Film/NoHoldsBarred'', hit theaters, the Wrestling/{{WW|E}}F thought it'd be a good idea to bring in the villain of the film, [[http://www.thewrestlinglegendsforum.com/wrestlecrap/zeus.html Zeus]], to battle Hulk in a WWF ring. They were never really clear on whether this was supposed to be the movie character come to life, or the actor assuming the character's persona to wreak havoc (in some promos, he'd lean one way, in others, the other), but one thing was absolutely clear throughout the entire angle: it was WrestleCrap.

* Due to both characters being from ManOfActionStudio to begin with, ''WesternAnimation/GeneratorRex'' had a special episode named ''WesternAnimation/Ben10GeneratorRexHeroesUnited'', involving Rex meeting [[WesternAnimation/{{Ben10}} Ben Tennyson]] (the [[WesternAnimation/Ben10UltimateAlien Ultimate Alien]] incarnation). A rare canon example, as it reveals more about Rex's backstory and provided Ben with a new alien form that actually made it to the next sequel series.

It makes quite a difference whether the crossover reveals that the characters have supposedly been sharing the same world the whole time; or if they're "just" from AnotherDimension. While not as big a deal if both series are "relatively" realistic, such as Crime Dramas, if each show has its own version of fantastic events a la {{Fantasy}} or ScienceFiction; then the implication is that these elements have been [[FantasyKitchenSink existing side by side the whole time, unaware of each other.]] It also makes for some great FridgeLogic. "Hey, Problem A for Cast B is no big deal, if Cast A and B are friends, why don't they just ask for help?" Of course, ReedRichardsIsUseless.

* Matt Trakker of ''WesternAnimation/{{MASK}}'' recently re-emerged as an action figure in the ''Franchise/GIJoe'' line, presumably because Kenner (''WesternAnimation/{{MASK}}''[='s=] manufacturer) merged with Hasbro (''Franchise/GIJoe''[='s=] manufacturer) years ago.

* Most of Creator/{{Hanna-Barbera}}'s cartoons.

** Also, the Animaniacs cameoed in the segment "Freakazoid And Friends".

* There was a competition between most of the major Fantasy series - based on popular opinion, not on what makes any sense. For example, [[Literature/TheWheelOfTime The Dragon Reborn]], [[Literature/DresdenFiles Harry Dresden]], [[Literature/TheKingkillerChronicle Kovthe]] all lost to muggles. Each one had a written description of the battle - and despite the implausibility, ''it was awesome''.

* ''LightNovel/BokuWaTomodachiGaSukunai'' And ''LightNovel/SeitokaiNoIchizon''.
* There's also the Minky Momo vs. Creamy Mami OVA.

** {{Gintama}} and SketDance had a crossover chapter for each manga, and two corresponding crossover episodes.
** {{Toriko}} and OnePiece had a crossover episode.
** And, most recently, OnePiece, DragonBallZ and {{Toriko}} had a crossover episode, though it obviously had no bearing on the continuity of any of the anime involved.