[[quoteright:338:[[VideoGame/DreamMixTVWorldFighters http://static.tvtropes.org/pmwiki/pub/images/mascot_fighter_ftw_1928.jpg]]]]
[[caption-width-right:338: Let's see... [[Franchise/{{Transformers}} Optimus Prime]], [[Anime/{{Beyblade}} Tyson]], [[VideoGame/AdventureIsland Master Higgins]], VideoGame/{{Bomberman}}, [[VideoGame/BloodyRoar Yugo]], VideoGame/TwinBee, [[Franchise/{{Castlevania}} Simon Belmont]]... just to name a few.]]

->''"So many heroes from so many dimensions! This is [[RuleOfCool pretty cool]]!"''
-->-- '''[[WesternAnimation/MyLifeAsATeenageRobot Jenny Wakeman]]''', ''[[VideoGame/NicktoonsUnite Nicktoons: Attack of the Toybots]]''

A {{crossover}} that involves characters from more than two shows or more than two {{ficton}}s.

More often than not, this is a mash up of series which do not have a strict sense of continuity or a clear UniverseBible. To lessen {{canon}}-faulting, especially with series that do have strict continuity, a new 'neutral' setting is made that offers equal footing for all the characters.

This rarely occurs in live action shows, unless a production company can be formed that holds copyrights to everything. Thus, this is much more common in animated series -- although you can generally expect TheBBC to pull one out of somewhere when ChildrenInNeed or UsefulNotes/ComicRelief rolls around.

It also becomes more viable the farther you get from {{canon}}, such as one-time TV specials and especially video games (''Franchise/KingdomHearts'', ''JumpSuperStars'', ''VideoGame/SuperRobotWars'', etc.)
As {{Story Arc}}s have become more prevalent, this practice has somewhat lessened, with shifts to strict [[TheVerse Verse]] building and explicit references.

This trope has become increasingly common in video games, especially those involving both licensed and original properties. These games, depending on how far or how deep they mine, can have interesting effects on the fiction chosen. Many long-gone and/or forgotten HumongousMecha shows, for example, often get a new lease on life, or even a brand-new sequel or remake, after making an appearance or two in a ''VideoGame/SuperRobotWars'' game. Similarly, the ''FireEmblem'' series was finally brought over to the US to great success after two of its characters made an appearance as unlockable fighters in ''VideoGame/SuperSmashBros Melee''.

Despite what you may think, this trope is OlderThanFeudalism. The ''{{Argonautica}}'' by Apollonius Rhodius (3rd century BCE) features nearly every ancient Greek mythical hero all going on a quest to find the Golden Fleece.

{{Sub Trope}}s:
* CrisisCrossover (a company-wide Massive Multiplayer Crossover)
** CrossThrough (a company-wide event that affects every series involved without having them cross over)
* DeconstructionCrossover (when the main purpose of using a Massive Multiplayer Crossover is {{Deconstruction}})
* MonsterMash (classical movie monsters)
* UltimateShowdownOfUltimateDestiny (When the Massive Multiplayer Crossover meets LetsYouAndHimFight)

See also PowerCreepPowerSeep and StoryBreakerTeamUp. AllStoriesAreRealSomewhere is related.


* [[MassiveMultiplayerCrossover/AnimeAndManga Anime and Manga]]
* MassiveMultiplayerCrossover/ComicBooks
* MassiveMultiplayerCrossover/FanWorks
* MassiveMultiplayerCrossover/{{Film}}
* MassiveMultiplayerCrossover/{{Literature}}
* MassiveMultiplayerCrossover/LiveActionTV
* MassiveMultiplayerCrossover/{{Music}}
* MassiveMultiplayerCrossover/{{Other}}
* MassiveMultiplayerCrossover/VideoGames
* MassiveMultiplayerCrossover/{{Webcomics}}
* MassiveMultiplayerCrossover/WebOriginal
* MassiveMultiplayerCrossover/WesternAnimation