History Main / AlternateIdentityAmnesia

* Both incarnations of Rose and Thorn of Franchise/TheDCU:
** In MediaNotes/TheGoldenAgeOfComicBooks you had a standard JekyllAndHyde case. At first Thorn was an enemy of the Jay Garrick [[ComicBook/TheFlash Flash]], and after being cured of Thorn, Rose Canton became the wife of the original ComicBook/GreenLantern. Too bad it couldn't last; Thorn resurfaced and Rose had to stop her for good with a HeroicSacrifice.
** MediaNotes/TheBronzeAgeOfComicBooks[=/=]ComicBook/PostCrisis Rose Forrest and Thorn are another story. Thorn is a BadassNormal superhero initially out to [[YouKilledMyFather bring the gang that her/their police officer father died against]] to justice. DependingOnTheWriter, either each knows the other exists, but don't remember what the other did while in charge, so they have to write to each other, or Thorn "awakens" with knowledge of whatever injustice Rose has witnessed, but Rose is completely unaware of this.

* ''ComicBook/MsMarvel'': When [[Characters/MarvelComicsCarolDanvers Carol Danvers]] [[ComicBook/MsMarvel1977 started out as a superhero]], she would involuntarily black out and change to her alter ego. She wasn't initially aware that she was a superhero. After a while, the line between the two started to blur, and they began fighting over who was in control, until the issue was resolved.
* ''ComicBook/BlazeOfGlory'': Lance Temple remembers nothing from his actions as the ComicBook/OutlawKid, other than a vague feeling that he had been there.
* ''ComicBook/WonderWoman'' [[ComicBook/WonderWoman1942 Vol 1]]: This is how ComicBook/{{Cheetah}} (Priscilla Rich) expressed her multiple identities in the Silver Age, with the Cheetah and Priscilla being unaware of each others' actions unless they saw physical or documentary evidence of it, and consequently [[TheKillerInMe try to foil their other persona's plots]]. In the Golden Age she was a vain murderous socialite who took up a costumed alter ego when superheroes were getting more attention than her.

** In UsefulNotes/TheGoldenAgeOfComicBooks you had a standard JekyllAndHyde case. At first Thorn was an enemy of the Jay Garrick [[ComicBook/TheFlash Flash]], and after being cured of Thorn, Rose Canton became the wife of the original ComicBook/GreenLantern. Too bad it couldn't last; Thorn resurfaced and Rose had to stop her for good with a HeroicSacrifice.
** UsefulNotes/TheBronzeAgeOfComicBooks[=/=]ComicBook/PostCrisis Rose Forrest and Thorn are another story. Thorn is a BadassNormal superhero initially out to [[YouKilledMyFather bring the gang that her/their police officer father died against]] to justice. DependingOnTheWriter, either each knows the other exists, but don't remember what the other did while in charge, so they have to write to each other, or Thorn "awakens" with knowledge of whatever injustice Rose has witnessed, but Rose is completely unaware of this.

* ''WesternAnimation/Rugrats2021": When Angelica's cured near the end of "The Werewoof Hunter,", she has little to no recollections of her actions as a wolf and instead is upset that her dress is ruined.

** Stan ends up going through something similar in "Cock of the Sleepwalk"; after his 100th kill, Stan keeps waking up to discover he's been doing good deeds he can't remember in his sleep. Eventually Stan watches a video made by "Sleepwalking Stan" explaining everything: "Sleepwalking Stan" is Stan's long suppressed conscience, determined to atone for all the people Stan's killed and to ensure that Stan never kills again.

** Played straight with Big Chill in ''WesternAnimation/Ben10AlienForce'', where Necrofriggians' reproductive instincts cause Ben to regularly turn into Big Chill unconciously and go around eating metal. Ben keeps no memory of those transformations.

* In a ''WesternAnimation/LegionOfSuperHeroes'' season 2 episode, Timber Wolf fears he's losing control of his transformation into his more feral state, the symptoms were mainly headaches and memory loss. However during one of his blackouts [[spoiler: he ended up murdering his father (actually a clone of him) in a fit of rage]] and in the aftermath he was hounded by most of the Legion for the crime. [[spoiler:The memory loss and headaches were caused by nanites his real father used to control him in an elaborate scheme to get him back.]]

* ''WesternAnimation/MrBogus'' apparently suffered from this in the first act of the episode "[[Recap/MrBogusS3E1NightmareOnBogusStreet Nightmare On Bogus Street]]". After Bogus became a werewolf from drinking a potion that he created, he puts Brattus [[StewedAlive in a stewpot]], when he suddenly turns back into his regular form once again, confused about how Brattus got into a stewpot. When Brattus explains to him what happened, Bogus denies ever doing such a thing to his own cousin, until he turns back into a werewolf again.

* When [[ComicBook/CarolDanvers Ms. Marvel]] [[ComicBook/MsMarvel1977 started out as a superhero]], she would involuntarily black out and change to her alter ego. She wasn't initially aware that she was a superhero. After a while, the line between the two started to blur, and they began fighting over who was in control, until the issue was resolved.

** In UsefulNotes/TheGoldenAgeOfComicBooks you had a standard JekyllAndHyde case. At first Thorn was an enemy of the Jay Garrick [[Franchise/TheFlash Flash]], and after being cured of Thorn, Rose Canton became the wife of the original Franchise/GreenLantern. Too bad it couldn't last; Thorn resurfaced and Rose had to stop her for good with a HeroicSacrifice.

* ''Franchise/SpiderMan'':

* ''Franchise/WonderWoman'' [[ComicBook/WonderWoman1942 Vol 1]]: This is how ComicBook/{{Cheetah}} (Priscilla Rich) expressed her multiple identities in the Silver Age, with the Cheetah and Priscilla being unaware of each others' actions unless they saw physical or documentary evidence of it, and consequently [[TheKillerInMe try to foil their other persona's plots]]. In the Golden Age she was a vain murderous socialite who took up a costumed alter ego when superheroes were getting more attention than her.

** In the ''Dragon Ball Super'' anime, Universe 6 Saiyan Kale originally didn't remembered what she did once she entered her Berserker form. However, this stops once she learns to control that form.

* In ''Manga/DemonSlayerKimetsuNoYaiba'', initially an intrinsic part of Zenitsu Agatsuma, one of the series' main characters, he has abysmal self-esteem which coupled with his cowardly nature makes the boy firmly believe he amounts to nothing as a warrior, despite being a certified demon slayer who has survived everything thrown at him; all of that pushed Zenitsu to create a kind of trance mode, while asleep, to answer the need of fighting demons because there is a few number of people who believe in him, which clashes with his own fear telling him to run away, as such the trance mode temporarily turns Zenitsu into a man without fear, but when he wakes up Zenitsu doesn't remember anything that happened during it, his innate self-doubt reinforcing that he is not a warrior.

This trope is about characters with a form of InvoluntaryShapeshifting or SuperPoweredEvilSide that causes them to suffer amnesia whenever they transform to their alternate form or self. Typically this trope is most often used in media with [[OurWerewolvesAreDifferent werewolves]] (or any other sort of [[OurWerebeastsAreDifferent werecreatures]]), though characters with a ''[[Literature/TheStrangeCaseOfDrJekyllAndMrHyde Jekyll And Hyde]]'' style SplitPersonality, DemonicPossession, MindControl, or an EnemyWithin may also suffer from this form of amnesia. When it happens it may be immediately noticeable to the character; they will freak out at suffering blackouts and [[WhatDidIDoLastNight waking up naked in a field]], covered in blood, and surrounded by animal carcasses[[note]](hopefully it'll be ''just'' animal carcasses; human body parts are also a distinct possibility)[[/note]].

* ''Literaure/TheSupernaturalsSeries'', Main character Daniel Price is a werewolf who at the best of times only has vague recollections of what hes does while he is in wolf form.

* Played with in ''LightNovel/TheGardenOfSinners'': at the beginning of chapter two, [[MultiGenderedSplitPersonalities Shiki and SHIKI]] share their body peacefully, and when one controls it, the other can remember everything they did afterwards. However, as a rift begins to form between the two personalities as a result of the plot events, SHIKI starts hiding his actions from Shiki, leaving her unable to remember what he did while in control of their body.

* ''Series/TheImperfects: Juan doesn't remember anything he does in chupacabra form.

* ''WesternAnimation/SofiaTheFirst'': In "Two Princesses and a Baby", when James is turned back to normal, he doesn't remember what he did [[FountainOfYouth as a baby.]]

* ''WesternAnimation/StevenUniverse'': Gems who have been under White Diamond's control have no memory of it after, as hinted by [[spoiler:Pink Diamond's original Pearl]] when she asks what happened after being freed, and confirmed in ''[[WesternAnimation/StevenUniverseFuture Future]]'' when she says she doesn't remember anything from the 8,000 years she was in that state.

* ''Manga/AyakashiTriangle'': Matsuri [[AmnesiaEpisode spends some time]] hypnotized into believing he was always a girl, showing a completely different personality that lack any of his original memories. After changing back, he regards the things he did (including [[JumpingTheGenderBarrier falling in love with Soga]]) as a "weird dream" that he doesn't dwell on.