History Main / SiblingFusion

* ''Fanfic/TheSpongeHouse'': In "Lona Loud", the Loud twins end up fused together because of one of the inventions of their ChildProdigy sister Lisa. They look like ConjoinedTwins and even their outfit is a cross between their outfits-- Lana's overalls, Lola's sash, one of Lana's shoes, and one of Lola's. At the end of the chapter, all their siblings, plus their parents, become fused with them. [[SnapBack They're fine in the next chapter, though.]]

** ''ComicBook/SpiderMan'': ''The Amazing Spider-Man'' #208 introduces twin brothers Hubert and Pinky Fusser. Both worked at the same company but in different professions; Hubert was a scientist while Pinky was a janitor. An accident occurs during one of Hubert's experiments causing the two brothers to merge together into a being known as Fusion the Twin Terror.

* ''TabletopGame/YuGiOh'': The Ojama Brothers (Ojama Yellow, Ojama Green and Ojama Black) can be fused into Ojama King.

* ''ComicBook/{{Hellboy}}'': Roger the Homonculus' older "brother" (a flawed prototype) spent years building a monstrously huge homonculus body for himself and Roger to TakeOverTheWorld. Roger feigns to accept and is swallowed, only to release his power (well, Liz's power he'd accidentally drained from her) to burn up the body and his brother. Roger then returns the power to Liz to save her life, rendering himself inert, but the Bureu gets him a battery that lets him function again.

** ''Franchise/SpiderMan'': ''Amazing Spider-Man'' Vol 1. Issue #208 introduces twin brothers Hubert and Pinky Fusser. Both worked at the same company but in different professions; Hubert was a scientist while Pinky was a janitor. An accident occurs during one of Hubert's experiments causing the two brothers to merge together into a being known as Fusion the Twin Terror.
* ''ComicBook/MortalKombatMalibuComics'': [[CanonForeigner Sing and Sang]] (pictured above) are a pair of twins who can merge into a warrior named Siang. Individually, they possess exceptional skill but when merged together their abilities double. [[spoiler:Unfortunately, they were no match for Goro, who forced them to defuse, killing Sang in the process]].

** ''ComicBook/GenerationX'': It is revealed in Issue #31 that the ComicBook/MonetStCroix we've been following is actually a gestalt being created by her younger twin sisters Claudette and Nicole merging together. The twins can also merge with their brother Emplate to form M-Plate.

* ''Anime/TransformersSuperGodMasterforce'': Decepticon Godmasters Buster and Hydra, whose alt-modes are a pair of jets, are able to combine into a single jet known as Darkwings.

* ''Manga/OnePiece'': Charlotte Newshi's Devil Fruit ability allows him to fuse with his nine decuplet siblings into a giant lanky figure with a SinisterScythe.

* In ''Fanfic/UniverseFalls'', Dipper and Mabel have a fused form.

* ''Franchise/UltraSeries'':
** ''Series/UltramanRB'': The brothers Ultraman Rosso and Blu can fuse into the super warrior, Ultraman Reube. They first do this in the final episode to defeat Leugocyte and avert the bad destiny where they die at its hands like their predecessors did.
** Starting from ''Film/UltramanRBTheMovieSelectTheCrystalOfBond'', Rosso and Blu can also fuse with Ultrawoman Grigio, who is the Ultrawoman form of the sister of their human hosts, into Ultraman Groob to defeat even stronger opponents.

* ''VideoGame/MortalKombatArmageddon'': In Mileena's ending, she defeats Blaze and his energy causes her and Kitana to temporarily fuse together. When they separate they discover they have swapped features; Mileena now has Kitana's beautiful face, while Kitana has Mileena's Tarkatan teeth. This allows Mileena to pose as her sister whom she has thrown into prison where she goes insane.

* In ''Webcomic/GirlGenius'', Baron Klaus Wulfenbach is the result of his parents stitching him together from the remains of their three sons after a grisly lab accident. Considering Klaus' success as an adventurer and ruler of Europa, it's hard to argue with the results.

* ''Literature/CallahansCrosstimeSaloon'': The [=MacDonald=] brothers doing a mental version of this in their debut story, as they're essentially one personality in two separate bodies but they didn't start that way. Interesting they're just telepathic brothers, not twins.

[[quoteright:350:[[ComicBook/MalibuComicsMortalKombat https://static.tvtropes.org/pmwiki/pub/images/bt03_10_2.jpg]]]]

[[quoteright:350:https://static.tvtropes.org/pmwiki/pub/images/bt03_10_2.jpg]]

* ''ComicBook/MalibuComicsMortalKombat'': [[CanonForeigner Sing and Sang]] (pictured above) are a pair of twins who can merge into a warrior named Siang. Individually, they possess exceptional skill but when merged together their abilities double. [[spoiler:Unfortunately, they were no match for Goro, who forced them to defuse, killing Sang in the process]].

* ''{{ComicBook/Hellboy}}'': Roger the Homonculus' older "brother" (a flawed prototype) spent years building a monstrously huge homonculus body for himself and Roger to TakeOverTheWorld. Roger feigns to accept and is swallowed, only to release his power (well, Liz's power he'd accidentally drained from her) to burn up the body and his brother. Roger then returns the power to Liz to save her life, rendering himself inert, but the Bureu gets him a battery that lets him function again.

[[folder:Mythology & Religion]]

* ''WesternAnimation/ThePowerpuffGirls2016'': The finale of "[[Recap/ThePowerpuffGirls2016S02E23PowerofFour Power of Four]]" has Bliss, Blossom, Bubbles and Buttercup join together into a construct of a bigger Powerpuff Girl to fight HIM.

* ''Webcomic/ShotgunShuffle'': while shopping for toys on Black Friday, Ellie's second-oldest sister Tarragon and her youngest sister Pumpkin randomly fuse together into a being called Pumpagon.

* ''Literature/CallahansCrosstimeSaloon'': The [=MacDonald=] brothers end up doing a mental version of this in their debut story, they're essentially one personality in two separate bodies but they didn't start that way. Interesting they're just telepathic brothers, not twins.
* ''Literature/TheBadPlace'': In the story's climax, Frank finally kills Candy by teleporting them both all over until they are both [[TeleFrag Tele-Fragged]] to death into a BodyHorror mishmash.

** ''Anime/DragonBallSuper'': During the Tournament of Power arc, Shin proposes the idea of Androids 17 and 18 fuse together using the Potara Earrings. Beerus acknowledges they would be quite compatible since they are twins and the resulting fusion would be very powerful. However, the idea is discarded after Whis explains that if the fused fighter is ringed out, it would count as both fighters being dropped out, resulting in two losses for their universe.