History Main / OlderAlterEgo

* Hono and Yuki from the ''Master of Mosquiton'' OVA both have an adult form, which seems to be the form in which they can most effectively use their elemental powers. It's used as an excuse for blatant fanservice in the case of Yuki, whose transformation is usually accompanied by boingy sound effects as her relevant curves (shown in extreme closeup) abruptly, and literally, pop out of nowhere.

* The manga ''[=~Instant Teen (Just Add Nuts!)~=]'' is centered around this trope. In a terrifyingly creepy manner.

Occasionally overlaps with SuperpoweredAlterEgo. Compare with ThirteenGoingOnThirty, SleepModeSize. When the change is more permanent, you have a PlotRelevantAgeUp.

* In GeneWolfe's ''Wizard Knight'' 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.

* One particular ThatGuyWithTheGlasses SlashFic casts [[AtopTheFourthWall Lewis Lovhaug]] as a high school student who uses a PowerRangers transmorpher to become the superhero "Linkara". While the age difference isn't major, Linkara is stated to be five years older than the teenage Lewis (making him roughly Mr. Lovhaug's ''actual'' age).

** Studio Pierrot would later use the same plot line in ''PersiaTheMagicFairy'', ''MagicalStarMagicalEmi'' and ''Magical Stage Fancy Lala''.

* Probably used first in the first ever mahou shoujo manga (though not the first anime - that was another show) ''{{Himitsu no Akko-chan}}'', which first appeared in 1963. The CuteWitch female lead, Atsuko Kagami aka Akko, had a MagicMirror that allowed her to [[MasterOfDisguise take up the appearance of other people]]. Obviously, more than once she aged herself up to help the rest.

* Also the premise of FancyLala, in which 9 year old Miho Shinohara becomes her 16 year old alterego Lala, who becomes a MagicIdolSinger.

Subtrope of SuperpoweredAlterEgo. Compare with ThirteenGoingOnThirty, SleepModeSize. When the change is more permanent, you have a PlotRelevantAgeUp.

** Studio Pierrot would later use the same plot line in ''Magical Fairy Persia'', ''{{Magical Star Magical Emi}}'' and ''Magical Stage Fancy Lala''.

* In ''JungleWaItsumoHaleNochiGuu'', Guu can change into a beautiful young woman, who is strong enough to defeat a bear.

* The 2000 series reboot of ''[[HeManAndTheMastersOfTheUniverse He-Man]]''. The original is more a case of ClarkKenting.

* UltimateSpiderMan does this... sort of. He's actually 16, but usually tells people he's in his twenties when he's in costume. No one really buys it.

* ''[[RanmaOneHalf Ranma 1/2]]'' features the character of Miss Hinako, a little girl who can temporarily become a full-grown woman by absorbing another person's BattleAura. The technique that lets her do this was taught to her by Happosai when she was a bedridden child (not out of the kindness of his heart - he was being chased by nurses [[DirtyOldMan for stealing their underwear]] and wanted her to knock them out with it); the full-grown woman is a closer reflection of her true age, as the technique delays her aging.

The wholesomeness of this idea is its main feature; that characters would run into rather {{squick}}y situations if they found boyfriends or girlfriends while changed is surprisingly common.

* ArchieComics Superhero ''[[http://en.wikipedia.org/wiki/The_Fly_(Archie_Comics) The Fly]]'' (also known as Fly Man) was originally one of these. Young orphan Tommy Troy was given a magic ring that allowed him to transform into an adult with insect-based powers. Unusually for this trope, the age differential didn't last. By the fifth issue Thomas Troy had aged a good ten years, gaining a law degree along the way, and was drained of any lingering trace of originality. (This was concurrent with the departure of the original Joe Simon/Jack Kirby creative team.)

** Studio Pierrot would later use the same plot line in ''Magical Fairy Persia'', ''Magical Star Magical Emi'' and ''Magical Stage Fancy Lala''.

* The manga ''[[{{ptitleszopjv22}} Instant Teen (Just Add Nuts!)]]'' is centered around this trope. In a terrifyingly creepy manner.

* In the ''[[Anime/{{Ptitlei015gc004kw4}} Pokémon]]'' movie ''Spell of the Unown'', Molly decides she'd like to be older, and they make it so.

* Justin in ''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 one third the age of the other character actors]], with no actual in-story handwave. He even shifted back to ten-year-old size when he removed his helmet.

** Similar thing happened to his MalibuComics CaptainErsatz, Prime. He tried to use the older form to get together with a girl he had a crush on, which really creeped her out. Meanwhile, an adult heroine was nursing a crush on Prime.

* Justin in 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 one third the age of the other character actors]], with no actual in-story handwave. He even shifted back to ten-year-old size when he removed his helmet.

* In ''Freakazoid!'', 16-year-old Dexter Douglas transformed into the title character after being sucked into the internet and spitted back out. Notably, his adult superhero persona is far ''less'' emotionally mature.

<<|AnimeTropes|>>

* This seems to be Evangeline's power in ''MahouSenseiNegima''; however it's revealed that her "adult form" is just an illusion. (Later in the manga, though, Negi breaks out "age pills" that he and crew use.)
** Which are stated when introduced to just cast the same illusion Evangeline uses. Evidently, this illusion is fully tactile, extends or reduces actual reach and height, and doesn't cover your clothes (which can end up falling off or getting very tight)... I'm guessing the term "illusion" just means it's temporary, doesn't change your actual lifespan, and doesn't affect internal things like muscle or (in)ability to get pregnant.
*** Of course, it's [[PlayingWithATrope played around with]]... due to the fact that she's ReallySevenHundredYearsOld and stuck in her current form because [[OurVampiresAreDifferent she's a vampire]], Evangeline's illusion actually makes her appear ''younger'' than she really is... it's just her true form looks even younger than ''that''.
** When in the Magic World, Negi does something similar by magically aging himself up. Naturally, the whole situation is complicated when one of his students falls in love with his aged-up self, thinking that it's Negi's cousin.

* The manga ''[[{{ptitleszopjv22}}Instant Teen (Just Add Nuts!)]]'' is centered around this trope. In a terrifyingly creepy manner.

* The manga ''Instant Teen (Just Add Nuts!)'' is centered around this trope. In a terrifyingly creepy manner.

* Den from HeavyMetal
* In Freakazoid! 16-year-old Dexter Douglas transformed into the title character after being sucked into the internet and spitted back out. Notably, his adult superhero persona is far ''less'' emotionally mature.

[[folder:Film]]
* Live-action example: the TomHanks movie ''Big''.
** A variation occurred in the film's DistaffCounterpart ''13 Going On 30''.
[[/folder]]