History Main / MergingMistake

One of the possible results in a TeleporterAccident or in a case of a TeleFrag, or a case of a faulty MergingMachine. Might result in a ClippedWingAngel situation. ShapeshifterMashup may be the result of this, but just as often it's an intentional result. Compare AssimilationBackfire.

* In ''VideoGame/Disgaea4APromiseUnforgotten'', Mao's Evil Transformation skill has him trapping his targets into a MergingMachine with a Slime, with the end result being a humanoid being wearing the Slime's skull which speaks gibberish. Which then explodes.

* ''WesternAnimation/CodenameKidsNextDoor'': In "[[Recap/CodenameKidsNextDoorSpecialTheGrimAdventuresOfTheKND The Grim Adventures of the KND]]", [[WesternAnimation/TheGrimAdventuresOfBillyAndMandy Billy]] confuses the Delightfulization chamber with a portable bath he and The Delightful Children from Down the Lane get fused into a Grim Reaper that assimilate almost ''every'' kid on Creator/CartoonNetwork.

* ''ComicBook/SpiderMan'': One of Spider-Man's most iconic foes, ComicBook/DoctorOctopus, came to be when scientist Otto Octavius was struck by radiation while wearing an advanced mechanical arms harness, causing them to fuse to his body and be controllable by his mind.
* In the ''ComicBook/TeenageMutantNinjaTurtlesMirage'' miniseries ''Bebop and Rocksteady Destroy Everything'' a time travel mishap leads to temporal duplicates of the eponymous villain duo getting a second dousing of {{mutagen|icGoo}} while in contact with each other. The result is a hideous amalgamation of their bodies supplementary material calls Bopsteady.

* ''Franchise/{{Godzilla}}'' fanfiction ''Fanfic/AbraxasHrodvitnon'': After King Ghidorah's left head, San, is severed, San revives Dr. Viivienne Graham's body stored inside his head and he metamorphoses her into a Ghidorah ArtificialHybrid while transferring his consciousness to the new second head that's growing on Vivienne's body. However, due to a combination of San not understanding how human bodies work and the new TwoBeingsOneBody being "born" too early, [[Characters/AbraxasHrodvitnonMonsterX Viv and San]]'s first fused form ends up [[BodyHorror painfully malformed and underdeveloped]], and it can't use the ShockAndAwe powers which Ghidorah possessed [[spoiler:until Chapter 6]].

* ''Literature/TheFly'' is a classic in terms of TeleporterAccident fusions, with Andre ending up having his hand and head switched up with that of a fly.
* ''Literature/CaptainUnderpants'': In ''The Big Bad Battle of the Bionic Booger Boy'', [[ChildProdigy Kid inventor]] Melvin attempts to fuse himself with an advanced robot of his own making, intending to turn himself into a bionic super-boy. But just as the fusion process is commencing, Melvin's cat allergies are triggered and he sneezes boogers out his nose, causing them to be fused as well and turning him into the Bionic Booger Boy.
* Creator/RobertSheckley has a short story (later expanded into a novel called ''Alchemical Marriage of Alistair Crompton'') where a person who was split into several personalities with artificial bodies as a treatment for schizophrenia seeks them in order to reintegrate. At the end, he finds them all and reintegrates... except they don't integrate into his personality but create a completely new one.

* ''TabletopGame/{{Warhammer}}'': Vilitch was the downtrodden younger brother of Thomin, apprenticed to the tribe's shaman while Thomin received the best warrior training in preparation for his becoming the tribe's chieftain. Vilitch prayed to Tzeentch that their fates might be switched. Instead, Tzeentch melded their bodies together, Vilitch casting spells and Thomin's body removing nearby threats. Vilitch saw no problem with this, using his newfound strength to enact a RoaringRampageOfRevenge against AllOfTheOtherReindeer.

* ''WesternAnimation/{{Mixels}}'' has one fusion option known as "Murps", where the result ends up a misshapen creature that still has the abilities of the original tribe members, but is unable to properly utilize them, often causing destruction to either themselves or to their environment.
* ''Toys/{{BIONICLE}}'': Inverted; Hakann uses the Spear of Fusion in reverse by accident, hitting Vezok and splitting him into Vezok and Vezon. This results in Vezok losing much of the intelligence that made him a GeniusBruiser, while Vezon becomes an incredibly intelligent being, but lacking in his original self's powers, most of his physical strength, and [[GeniusDitz what sanity there was]].

* ''VideoGame/DayOfTheTentacle'': The finale of the game involves Bernard, Laverne and Hoagie climbing into one timemachine to chase down Purple Tentacle in the past. Dr. Fred tries to object, citing ''Literature/TheFly'' as a reason as why they should not go into the time machine. The end result involves the trio becoming a three-headed fusion of themselves with Hoagie's fat upper body and Laverne's gangly lower half. [[spoiler:The epilogue reveals that they didn't actually fuse together, but they're all tangled together and most of their body parts are stuck in Hoagie's shirt.]]
* Chaosmon from ''Franchise/{{Digimon}}'' is a result of an incomplete DNA Digivolution between [=BanchoLeomon=] and Darkdramon/Valdurmon, leaving it with two Digicores instead of a combined one, and is considered a GameBreakingBug in-universe. [=UltimateKhaosmon=] is another example, this time being a fusion of [=BanchoLeomon=], Darkdramon, Valdurmon and Kentaurosmon, whose powers are too much to contain in one body, leaving it being a withered out creature with four massive arms and two giant eyes which are actually two Digicores that it can't contain in its body.
* In ''VideoGame/Disgaea4APromiseUnforgotten'', Mao's Evil Transformation skill has him trapping his targets into a MergingMachine with a Slime, with the end result being a humanoid being wearing the Slime's skull which speaks gibberish. Which then explodes.

* One of the biggest threats in ''Martian Reunification Gothic'' is a virus the three protagonists are infected with at the beginning that forcibly merges other people with the virus together into hideous monsters, forcing them to stay in different rooms than each other. Fused monsters born out of scientists are also recurring enemies.

* At the climax of ''Videogame/Tron20'', the three F-con executives try to enter the cyberspace world in a last-ditch effort to stop the PlayerCharacter from thwarting their plans. [[spoiler:However, because the correction algorhythms of the digitizing laser have been removed at this point, they end up merging into a three-headed monstrosity that is defeated by the PlayerCharacter and is trapped on a storage medium afterwards.]]

* In the second half of the sixth episode of ''WebAnimation/{{Confinement}}'' Connor and several other people escape from the infinite IKEA using a staple gun with the ability to teleport what it shoots. It also turns out that if it is used to teleport multiple people in a short time it has the side effect of causing them to fuse together into a mass of BodyHorror. Connor is able to escape from the fusion thanks to his regeneration ability while everyone else isn't so lucky.

[[folder:Web Original]]
* ''Literature/WhateleyUniverse'': The Fury Twins, who merge into one being, but one time, they got stuck part-way defusing, and needed MadScientist help to get unstuck.
[[/folder]]

* In the ''WesternAnimation/Ben10'' episode "Dr. Animo and the Mutant Ray", this happens when Ben accidentally breaks part of the Omnitrix, resulting in fusions of his alien forms that cause more harm than good - Four Arms gets merged with Stinkfly, resulting in a hunk of muscle that can't fly very well; and [[FishPeople Ripjaws]] ends up fused with [[PlayingWithFire Heatblast]], which goes about as well as you'd expect.
** This also goes to an extreme with Kevin 11. After absorbing energy from the Omnitrix, he only gets one episode to impersonate Ben's forms, before [[spoiler: being unwillingly turned into a [[BodyHorror disturbing permanent mishmash of almost every one of them]] at once.]]

* The green wizard Carolinus from ''WesternAnimation/TheFlightOfDragons'' sees TheHero plummeting to certain doom, and docile dragon Gorbash unable to descend fast enough to catch him. Carolinus tries to invoke a magic spell to speed up Gorbash, but being pressed for time, Carolinus can't assemble the Latin phraseology completely, and concludes with a general-purpose "Kala!" The result is TheChosenOne being merged with Gorbash, becoming a modern-day man in the body of a fantasy realm dragon.
* ''The Grim Adventures Of KND'': After Billy confuses the Delightfulization chamber with a portable bath he and The Delightful Children from Down the Lane get fused into a Grim Reaper that assimilate almost ''every'' kid on Cartoon Network.
* In the episode "Canderemy" from ''WesternAnimation/PhineasAndFerb'', Candace and her crush Jeremy are fused together at the waist by one of her brothers' inventions. Eventually, the boys zap them together to form one bizarre fusion with two hair colors and four eyes.
* In the last season of the original ''WesternAnimation/{{Reboot}}'' series, Bob merges with his broken Keytool Glitch because that's the only way to make use of Glitch's Keytool abilities which are needed to escape the Web. In the revival season that takes place after the original series it's revealed that the merging was unstable precisely because Glitch was damaged. Glitch-Bob was unstable as a result and risked total fragmentation if he kept using his powers.
* In ''WesternAnimation/SpongeBobSquarePants'' episode "[=SquidBob TentaclePants=]", [=SpongeBob=] and Squidward get accidentally fused together in Sandy's teleportation device. In the end of the episode, everyone got fused together when Squidward tries to mess with an unfusion device.

** The abominations that are [[spoiler:the cluster experiments, which turned out to be horrifying amalgamates of shattered gem shards in a state of artificial forced fusion. The full-sized cluster that was buried in the Earth, which is comprised of millions of gem shards, would have formed big enough to destroy the Earth from the inside. Good thing it didn't. ]]
** The two times [[spoiler:Jasper]] tried fusing, it ended badly for her. The first time [[spoiler:she forcibly fused with Lapis Lazuli to form Malachite, but didn't count on Lapis taking over and chaining themselves to the bottom of the ocean]]. The second time [[spoiler:she fused with a corrupted Gem Monster, and ended up contracting its corruption]].

* In ''WesternAnimation/TeenageMutantNinjaTurtles1987'', this is how Baxter Stockman underwent his infamous fly transformation. When Baxter was sent to Dimension X, Krang didn't see any use for him, and so threw him into the Technodrome's Disintegrator Unit. However, a fly that ended up coming to Dimension X with him ended up in the unit as well, causing a malfunction in which Baxter was cross-mutated with the insect, leaving him in the form he would remain for the remainder of his appearances.

* ''Franchise/SpiderMan'': One of Spider-Man's most iconic foes, ComicBook/DoctorOctopus, came to be when scientist Otto Octavius was struck by radiation while wearing an advanced mechanical arms harness, causing them to fuse to his body and be controllable by his mind.

* In ''WesternAnimation/SpongeBobSquarePants'' episode "[=SquidBob TentaclePants=]", [=SpongeBob=] and Squidward get accidentally fused together in Sandy's teleportation device. In the end of the episode, everyone got fused together when Squidward tries to mess with an unfusion device.

* The green wizard Carolinus from ''WesternAnimation/TheFlightOfDragons'' sees TheHero plummeting to certain doom, and docile dragon Gorbash unable to descend fast enough to catch him. Carolinus tries to invoke a magic spell to speed up Gorbash, but being pressed for time, Carolinus can't assemble the Latin phraseology completely, and concludes with a general-purpose "Kala!" The result is TheChosenOne being merged with Gorbash, becoming a modern-day man in the body of a fantasy realm dragon.

* ''The Grim Adventures Of KND'': After Billy confuses the Delightfulization chamber with a portable bath he and The Delightful Children from Down the Lane get fused into a Grim Reaper that assimilate almost ''every'' kid on Cartoon Network.
* In the episode "Canderemy" from ''WesternAnimation/PhineasAndFerb'', Candace and her crush Jeremy are fused together at the waist by one of her brothers' inventions. Eventually, the boys zap them together to form one bizarre fusion with two hair colors and four eyes.
* In the last season of the original ''WesternAnimation/{{Reboot}}'' series, Bob merges with his broken Keytool Glitch because that's the only way to make use of Glitch's Keytool abilities which are needed to escape the Web. In the revival season that takes place after the original series it's revealed that the merging was unstable precisely because Glitch was damaged. Glitch-Bob was unstable as a result and risked total fragmentation if he kept using his powers.
* ''WesternAnimation/DuckTales2017'': The Stone of What Was has the power to fuse two creatures that touch it at the same time into one being. While many of its creations are mere MixAndMatchCritters, some of Don Karnage's pirates fuse with animals (an ant, a snail and a parrot) and each other into [[BodyHorror horrifying freaks]].

[[quoteright:279:[[WesternAnimation/SpongebobSquarepants https://static.tvtropes.org/pmwiki/pub/images/merging.png]]]]

* In the ''ComicBook/TeenageMutantNinjaTurtles'' miniseries ''Bebop and Rocksteady Destroy Everything'' a time travel mishap leads to temporal duplicates of the eponymous villain duo getting a second dousing of {{mutagen|icGoo}} while in contact with each other. The result is a hideous amalgamation of their bodies supplementary material calls Bopsteady.

* In ''VideoGame/TheGameOfLife'', there are several ways in which a "glider synthesis" (colliding gliders together to produce new objects) can go wrong. To be valid, a synthesis must be able to be rewound indefinitely while still eventually leading to the same result. If not checked for, an attempt to rewind the synthesis will cause gliders traveling in different directions to collide prematurely. Even if the synthesis is valid, a single glider being out of place by even one cell or one generation can ruin the synthesis and produce a completely different object.

* ''WesternAnimation/DuckTales2017'': The Stone of What Was has the power to fuse two creatures that touch it at the same time into one being. While many of its creations are mere MixAndMatchCritters, some of Don Karnage's pirates fuse with animals (an ant, a snail and a parrot) and each other into [[BodyHorrors horrifying freaks]].

* ''WesternAnimation/DuckTales2017'': The Stone of What Was has the power to fuse two creatures that touch it at the same time into one being. While many of its creations are mere MixAndMatchCritters, some of Don Karnage's pirates fuse with animals (an ant, a snail and a parrot) and each other into horrifying freaks.

[[quoteright:280:[[WesternAnimation/SpongebobSquarepants https://static.tvtropes.org/pmwiki/pub/images/merging.png]]]]
[[caption-width-right:280:''[[VideoGame/Persona5 Well, now... a most unexpected turn of events...!]]'']]

* ''Anime/YuGiOh'': One Duel against Kaiba during the show’s [[EarlyInstallmentWeirdness first season]] has Yugi fusing his undead monster with his opponent's living monster. The monsters can’t properly combine, so Kaiba’s monster becomes weaker every turn.

[[quoteright:350:[[WesternAnimation/SpongebobSquarepants https://static.tvtropes.org/pmwiki/pub/images/spongebob_merging.png]]]]
[[caption-width-right:350:''[[VideoGame/Persona5 Well, now... a most unexpected turn of events...!]]'']]

[[FusionDance Fusions]] are cool. They allow two beings to merge together to create a stronger being. However, fusions are in practice incredibly dangerous. Whether it was done with science, biologically or through magic, even a slightest mistake can make the results be less than ideal if you're lucky.

How the fusion can result in a failure varies. Sometimes the result is [[BodyHorror a mesh of body parts or full of deformities]]. Sometimes the fusion at first looks fine but is actually incredibly unstable, and will fall apart at some point. Sometimes the fusion wasn't intended to happen in the first place, what just increases the chance of it being really wrong. The only real requirement is that the fusion needs to be physical in nature.

** Potara earring fusions are foolproof, and to fuse you need only have the two fusees wear one matching earring on opposite ears. If within range, they will fuse perfectly into a much more powerful fusion -- and if at least one of the fusees is a Kai, the new fusion is permanent barring a wish to separate from each other to the series' titular MacGuffin. If neither fusee is a Kai, the fusion instead lasts twice as long under regular circumstances as the FusionDance. But despite their foolproof nature, there exists two cases so far of Fusion going awry.

* Creator/RobertSheckley has a short story (later expanded into a novel called ''Alchemical Marriage of Alistair Crompton'') where a person who was split into several personalities with artificial bodies as treatment for schizophrenia seeks them in order to reintegrate. At the end, he finds them all and reintegrates... except they don't integrate into his personality, but create a completely new one.

* ''VideoGame/DayOfTheTentacle'': The finale of the game involves Bernard, Laverne and Hoagie climbing into one time machine to chase down Purple Tentacle in the past. Dr. Fred tries to object, citing ''Literature/TheFly'' as a reason as why they should not go into the time machine. The end result involves the trio becoming a three-headed fusion of themselves with Hoagie's fat upper body and Laverne's gangly lower half. [[spoiler:The epilogue reveals that they didn't actually fuse together, but they're all tangled together and most of their body parts are stuck in Hoagie's shirt.]]