History Main / OlderAlterEgo

* [[Creator/MarkWaid Mark Waid's]] ''Captain Kid'' inverts with forty-something Chris Vargas gaining the ability into the titular teenaged superhero.

* ''ComicBook/{{Thunderbunny}}'': Lesser-known 80s comic in which a boy transforms into a grownup antro rabbit superhero.

** Studio Pierrot would later use the same plot line in ''Anime/PersiaTheMagicFairy'', ''Anime/MagicalEmiTheMagicStar'' and ''Anime/MagicalStageFancyLala''.

* ''Anime/MagicalAngelCreamyMami'' in which 10-year-old Yu uses magic to become a 16-year-old idol singer under the alias of Creamy Mami.

** Studio Pierrot would later use the same plot line in ''Anime/PersiaTheMagicFairy'', ''Anime/MagicalStarMagicalEmi'' and ''Anime/MagicalStageFancyLala''.

** And then there's Neptune and Plutia who also transform from looking like early teenagers to fully fledged adults.

** And then there's also Neptune and Plutia who also transform from looking like early teenagers to fully fledged adults.

* One arc of ''ComicBook/SupermanBatman'' has the titular duo encounter a team of expies of ComicBook/TheUltimates. The ComicBook/IncredibleHulk expy is a cute little girl who turns into a big blue monster.

** Aguri Madoka (Natalie) from ''[[Anime/DokiDokiPrettyCure Glitter Force: Doki Doki]]'' is a fourth-grader, while her teenage 17 year old-looking alter-ego Cure Ace (Glitter Ace) is considerably ''older'' than her 14-year-old companions.

* ''WesternAnimation/YoungJustice''. Becomes a plot point when there's an EvilPlan to make all the adults disappear. They've actually been shunted to AnotherDimension where they assume that all the children have disappeared, and only discover the truth after Captain Marvel changes to his adult form. He then changes back and forth to coordinate efforts between the adults and children. This is the first time everyone finds out about Marvel's YoungerAlterEgo, and a later episode has the Justice League debating whether Captain Marvel should remain in the League given that he's legally still an adolescent.

* ''[[Anime/NanakaSixSeventeen Nanaka 6/17]]'':

* ''Manga/MarvelousMelmo'' is another early MagicalGirl example, in which the 9-year-old heroine uses magic candies to age into an attractive 19-year-old {{Fanservice}}-tastic version of herself.

* ''Manga/MarvelousMelmo'' is another early MagicalGirl example, in which the 9-year-old heroine uses magic candies to age into an attractive 19-year-old PantyShot-tastic version of herself.

** Although regular gems are TheAgeless, their fusions can look vaguely older: Ruby and Sapphire look somewhat child-like, but [[spoiler:Garnet]] is clearly an adult.
** This is PlayedForDrama in ''WesternAnimation/StevenUniverseFuture''. Jasper's training plus Steven's poor mental health causes him to become DrunkWithPower, drastically changing his appearance and physique so he looks like a JerkJock. After [[spoiler:he accidentally shatters Jasper]], he's back to his usual self, implying that this was an example of age-related shapeshifting.

* Numbuh Two in ''WesternAnimation/CodenameKidsNextDoor'' uses his technology to turn himself into a teenager, and ends up in love with Cree. Unfortunately, the transformation is only temporary, and when Cree finds out, she is disgusted that she was on a date with a kid.

* The author of ''Full Moon'' (Creator/ArinaTanemura) also created a manga that inverted the trope, ''31 Ai Dream (Idol Dreams)'' where a depressed 31 year old office worker feels she's wasted her youth and attempts to complete suicide but she is stopped by an old school mate who has developed a de-aging drug which will revert her back to 15 (its effects last 5-6 hours per consumption) which he offers to her, she uses it to become an Idol Singer.

* Inverted in ''Manga/IdolDreams''; like many examples, main character Chikage lives a double life as an IdolSinger named Akari, but she does this by aging herself down from 31 years old to 15 with an age-altering drug.

* In the ''VideoGame/DevilMayCry3'' manga, Alice (who resembles the protagonist from ''Literature/AliceInWonderland'') actually goes so far as to trade her innocence to demons for the sake of becoming older and more attractive.

* The author of ''Full Moon'' (Creator/ArinaTanemura) also created a manga that inverted the trope, ''31 Ai Dream (Idol Dreams)'' where a depressed 31 year old office worker feels she's wasted her youth and attempts to complete suicide but she is stopped by an old school mate who has developed a de-aging drug which will revert her back to 15 (it's effects that last 5-6 hours) which he offers to her, she uses it to become an Idol Singer.

* ''WesternAnimation/YoungJustice''. Becomes a plot point when there's an EvilPlan to make all the adults disappear. They've actually been shunted to AnotherDimension where they assume that all the children have disappeared, and only discover the truth after Captain Marvel changes to his adult form. He then changes back and forth to coordinate efforts between the adults and children. Incidentally is the first time everyone finds out about this trope, and a later episode has the Justice League debating whether Captain Marvel should remain in the League given that he's legally still an adolescent.

** Becomes a plot point in ''WesternAnimation/YoungJustice'' when he is able to travel between all-kids and all-adults parallel worlds.

[[caption-width-right:317:Don't trust him Billy! [[Website/SuperDickery Superman has an angle!]]]]

* ''Franchise/SuperSentai'''s ''Series/GoseiSentaiDairanger'': This series features a 9-year-old that became the Kiba Ranger with the same circumstances as ''Power Rangers Turbo'''s Justin. His living sword speaks for him while he is hiding his identity from the other Dairangers.

* ''ComicBook/{{Thunderbunny}}''. (Lesser-known 80s comic in which a boy transforms into a grownup antro rabbit superhero).

* This is one of the powers of the Grass Guardian in ''[[Fanfic/GuardiansOfPokemon Guardians of Pokémon]]''. Later, [[spoiler:Pikachu]] also gets the power to temporarily age up [[spoiler:using the Thunder Stone]]... but after the transformation has run out, she temporarily becomes even ''younger'' than usual.

* The main characters of ''Series/BigBadBeetleborgs'' are all kids who thanks to a Phantasm called Flabber [[AscendedFanboy become their favorite heroes]]. (Note that only the ''Dairanger'' example has to get around adult-sized heroes sounding like kids. Even people who know the kids and meet the heroes don't ever say a word about the voice thing.

* Justin in ''Series/PowerRangersTurbo'', mostly as a result of the suit-actor being the same age as the rest of the suit-actors, while the character actor was about [[DawsonCasting half the age of the other character actors]], with no actual in-story handwave. He even shifted back to twelve-year-old size when he removed his helmet. (We never saw that happen directly, sadly. When the Rangers would be suited but unhelmeted around the base, Justin would be wearing a kid-sized suit, all size-shifting happening offscreen.)

* ''Franchise/SuperSentai'''s ''Series/GoseiSentaiDairanger'': This series features a 9-year-old that became the Kiba Ranger with the same circumstances. His living sword speaks for him while he is hiding his identity from the other Dairangers.

* Although very rare in ''Franchise/PrettyCure'', it does happen:

* The last episode of ''Anime/MagicalWitchPuniechan'' uses this as part of a power upgrade. In it, the sisters of the main character, Punie, become older in an attempt to beat her and take the throne from her. Unfortunatly, they fail miserably.

* ''ComicBook/{{Thunderbunny}}''. (Lesser-known 80s comic in which a boy transforms into a grownup anthro rabbit superhero).

* In Creator/GeneWolfe's ''Literature/WizardKnight'' series, the hero is a young kid who is transformed into a brawny KnightInShiningArmor in a fantasy world but is still as naive as your typical KidHero.

** The ''TabletopGame/HaltEvilDoer'' setting has brother and sister counterparts to Billy and Mary: Ken and Jun Masterson are twins born to Otherworld royalty, spirited out of Otherworld for their own protection as babies, and who unexpectedly awoke their true power at the age of eight, becoming the adult heroes Ultimatum and Valkyrie. As of the published setting, they're sixteen, but their heroic forms are still noticably older.