History Main / PlotRelevantAgeUp

* In ''WesternAnimation/TheLandBeforeTime'', Spike is shown hatching in a patch of grass Ducky finds his egg in. Cut to outside the grass, and Spike inexplicably comes out looking the same age as the rest of the main cast. He could just be big for his age.
* Several movie franchises play with this, specifically ''Franchise/TheLionKing'' and ''WesternAnimation/IceAge''. As the kids will age up, but no-one else shows any signs of aging at all. Simba and Peaches will grow into teenagers while all the other characters (aside from other kids) seem to be frozen in time. Timon and Pumbaa are probably the worst offenders in movie history, as they're adults when Simba is a baby. Cue when Simba is a father – even when his daughter reaches adulthood, they're still exactly the same. Possibly [[JustifiedTrope justified]], as for most non-human species the aging from childhood to adulthood is a matter of a mere year or two. Lions reach sexual maturity between 3-4 years old and live to about 16, while meerkats reach maturity at 1 and live on average to 6-10.

* In ''Film/{{Dinocroc}}'', the titular creature is roughly the size of a large dog in the opening scenes. Cut to a few days later and it's grown to the size of a large truck able to fit an entire teenager over the length of its jaws. Partially justified as it was engineered to have a ludicrously fast growth rate and was said to have previously grown about half a meter in a single day.

* ''Webcomic/ElGoonishShive'':
** It has the unusual situation of [[spoiler: two characters having their ''souls'' aged by having them experience the normal lives of AlternateUniverse versions of themselves during their dreams. It is [[http://www.egscomics.com/?date=2006-05-03 explained later]] that this was done to prevent insanity caused by them having been created with adult bodies and minds but newly-formed souls]], by giving them their own childhood memories.
** Also in EGS, the ''in''ability to rapidly age the Lycanthropes plays a small but important part in Grace's BackStory.

* The Tweebs in the fourth season of ''WesternAnimation/KimPossible'' are an interesting variation: although their art makes them look older, they are not acknowledged as such, but merely advance-placed into Kim's high school during the PostScriptSeason.

* In ''Anime/RahXephon'', [[spoiler:Haruka and Ayato were the same age in the past; at the time of the series, Ayato is 17 and Haruka is 29 due to time passing differently inside and outside of Tokyo]]

* ''VideoGame/JakAndDaxter'': Jak/[[spoiler:Prince Mar]] was sent back in time as a toddler at the end of [[VideoGame/JakIIRenegade the second game]] so he could one day return to [[RightfulKingReturns overthrow Baron Praxis]] and stop the wars against the Metal Heads and Dark Makers in his teenhood. Due to this, [[TheGoodKing Damas]] doesn't realize that Jak is his missing son [[spoiler:and dies asking him to locate Mar without knowing his LastRequest was fulfilled]].

* "Manga/{{Bleach}}":
** [[spoiler:Nelliel Tu Odelschwanck]] had her powers sealed away before the story began, resulting in her spirit becoming smaller and childlike. She regains her powers while trying to defend Ichigo, but can only maintain her true appearance for a few minutes. Urahara eventually gives her a device that stabilizes her Reiatsu and allows her to remain as an adult.
** After some rigorous offscreen training in the dangai, where time passes exorbitantly fast, [[spoiler: Ichigo]] returns looking several years older.

* [[spoiler:Nelliel Tu Odelschwanck]], formerly [[spoiler:Nel]], of ''Manga/{{Bleach}}'' temporarily grows back to her true age when Ichigo suffers a severe beating from Nnoitra. She promptly returns the latter the favor.
** After some rigorous offscreen training in the dangai, where time passes exorbitantly fast, [[spoiler: Ichigo]] returns looking [[ShesAllGrownUp all grown up.]]
** Eventually, in the Thousand-Year Blood War arc [[spoiler:Urahara gives Nel a device that allows her to grow to her true age ''and'' stay as such, so she can fight alongside Ichigo and his TrueCompanions from then on.]]

* Both the Powerpuff Girls and the Rowdyruff Boys undergo this in ''[[https://www.fanfiction.net/s/13589147/1/Abandon-All-Hope-Embrace-All-Chaos Abandon All Hope, Embrace All Chaos]]'' with the Emperor training them to become his elite warriors against Chaos. Deconstructed as several characters feel like the six's childhoods have been stolen from them for the sake of a war.

** Eventually, in the Thousand Year Blood War arc [[spoiler:Urahara gives Nel a device that allows her to grow to her true age ''and'' stay as such, so she can fight alongside Ichigo and his TrueCompanions from then on.]]

* ''Manga/Reborn2004'': Instead of 8 year old Futa also being involved in the Future Arc, his 18 year old self stays to be a competent supporting cast. Doesn't happen with Lambo and I-pin, though.

** Eventually, in the Vandenreich arc [[spoiler: Urahara gives Nel a device that allows her to grow to her true age ''and'' stay as such, so she can fight alongside Ichigo and the TrueCompanions from then on.]]

* ''Anime/DoraemonNobitasDinosaur'' have Nobita finding a baby dinosaur and deciding to show it off to his friends, Suneo, Gian and Shizuka. But Nobita wants to show them a full-sized dinosaur (lest having Suneo make fun of him by calling it a "badly-disguised lizard"), so Doraemon produced one of his gadgets - the Instant Age-Up Light.

** ''ComicBook/TheAvengers'' #200. Ms. Marvel is impregnated, gives birth, and her child ages to adulthood within minutes.

* Hana-chan does this in the first episode of ''Anime/OjamajoDoremi Dokkan'', turning from a baby to an 11-year-old girl so she can go to school with her "mamas" who raised her from Sharp to Motto.

* In ''Franchise/OnePiece'', eight-year-old Kozuki Momonosuke gets Shinobu to age him up by twenty years so he could assist Luffy in his ongoing battle with Kaido, debuting in his adult dragon form in Chapter 1023. His human form has yet to be shown, but Shinobu was moved to tears upon seeing it, describing it as looking identical to someone else.

* One of the many effects of the TimeyWimeyBall in ''Webcomic/{{Enjuhneer}}'' is that characters stay the same age for an entire year, then suddenly change in a manner comparative to [[LevelUp levelling up]]. This can cause [[LittleBitBeastly drastic effects]], or can be as simple as suddenly acquiring a pair of WhiteGloves with no idea where they came from.

* ''ComicBook/GoldDigger'' has Brianna, an accidental [[CloningBlues composite clone]] of Brittany and Gina. She was born fully grown, with both sets of memories, and had to establish an identity for herself. It was eventually established that some of her more childish personality traits owe to the fact that her ''soul'' is still her real, chronological age, and never got to experience a real childhood. Her [[spoiler:sadly deceased]] granny was the only person insightful enough to treat her with the level of affection she would give a little girl.

* ''VideoGame/MetalGear''-[[TheVerse verse]] [[CloningBlues clones]] age normally up until the time when senescence[[note]]the last cycles of aging[[/note]] starts to set in, which then hits them like a train. This was used to age the main character, Snake, from a young and handsome hero in his early thirties into an OlderAndWiser [[CoolOldGuy forty-something]] in the space of only two years in chronology. In ''Metal Gear Solid 4'', despite the fact that he is chronologically in his early forties, he is, by all appearances and genetic testing well into his seventies. Heck, he looks older than some eighty year olds in the game. [[{{Foreshadowing}} Prior to this]], Snake and Raiden had seen how hard the aging hits with Solidus Snake in ''Metal Gear Solid 2''--despite being chronologically younger than Solid Snake, the Patriots had engaged his accelerated aging process early so that he would appear to be middle-aged during the events of the first game and thus [[spoiler:would be able to fit in the role of being the Patriots' puppet President of the United States. As the elections were rigged, the Patriots needed to make their candidate seems as plausible as possible to maintain their charade.]] By the time of the game's events, Solidus's accelerated aging has gone even further and he rather resembles Snake in Metal Gear Solid 4.

** It has the unusual situation of [[spoiler: two characters having their ''souls'' aged by having them experience the normal lives of AlternateUniverse versions of themselves during their dreams. It is [[http://www.egscomics.com/?date=2006-05-03 explained later]] that this was done to prevent insanity caused by them having been [[CloningBlues created with adult bodies and minds but newly-formed souls]], by giving them their own childhood memories.]]

* Happens to Lloyd in ''WesternAnimation/{{Ninjago}}'' at the end of the episode "Child's Play" as a result of using Tomorrow's Tea to turn the Grundle back into bones. This physically ages him from a kid into a young adult, prompting the final battle with his father to draw closer. Curiously, WordOfGod says that he is still a child mentally, though certain events afterwards have caused him to mature at a quicker pace.

* Hana-chan does this in the first episode of ''Anime/OjamajoDoremi Dokkan'', turning from a baby to an 11-year-old girl so she can go to school with her mommies.

* ''WesternAnimation/{{Kaeloo}}'': In one episode Kaeloo finds out that Stumpy, who is ten, acts like a KiddieKid because his family stopped celebrating his birthday ever since he was five, which leaves him mentally stuck at the age of five. Kaeloo holds a "multibirthday" party to make up for the remaining five years, and since magic exists in Smileyland this somehow ages him up to the proper age. Unfortunately, the other guests at the party are excited to see the magic in action and keep celebrating more birthdays until Stumpy is aged up into a 30-year-old man. [[StatusQuo He's back to normal by the next episode.]]

'''Margo:''' ''Literature/{{Twilight}}''.\\

* In ''Anime/TowardTheTerra'', when Nazca is [[EarthShatteringKaboom under attack]] by the [[WaveMotionGun Meggido]] the seven Children of the Mu instantly age themselves from toddler to teen and teleport themselves into space to reenforce the shield Blue and Jomey have just created.

* ''Franchise/StarTrek'', from ''[[Series/StarTrekTheNextGeneration The Next Generation]]'' on, uses this a lot, almost always in the form of using BizarreAlienBiology to HandWave {{SORAS}}:
** ''Series/StarTrekDeepSpaceNine'' actually did a one-shot of this trope, where the O'Briens' toddler daughter Molly fell into a time portal, and grew to adulthood before coming back. Fortunately, when she went through the portal again, it sent her to the same time as before, and she sent her younger self back.
** They also did this with Worf's son Alexander, justifying it by establishing that Klingon children mature very fast. Alexander was played by several different actors and always behaved about as old as he looked. ''[[Series/StarTrekDeepSpaceNine Deep Space Nine]]'' really pushed it by making him physically and mentally a young adult at the chronological age of, oh, seven. (The fast aging is especially odd if you consider that Klingons also live longer than humans, a fact established so Klingons from TheOriginalSeries could show up.)
** Klingons aren't alone in this, by the way. The most extreme example is ''[[Series/StarTrekVoyager Voyager]]'''s Kes, whose race has a nine-year lifespan. In one alternate future episode, Kes had a daughter with Tom Paris... and that daughter was old enough to marry Harry Kim within a year or two.
*** Deep Space 9 also has the Jem'Hadar, who age incredibly fast because of special genetic modifications.
** Voyager also has Naomi Wildman who is 1/2 Human - 1/2 Ktarian. At age 2 chronologically, she looks and acts like an 8-year-old Human. This was justified InUniverse by her half-alien biology. Another side effect is her gestation was approximately 18 months.
** Another ''Series/StarTrekTheNextGeneration'' example: At the start of season two, Troi goes from being newly pregnant to having a baby in a few days. The kid then grows from babyhood to about ten years old in a similar space of time, before "dying". [[spoiler: Turns out the "kid" was a benign energy-based alien who wanted to experience corporeal existence, and was grateful for all the affection Troi showed "him".]] This was actually one of the first episodes to [[GoodTroiEpisode really cement Troi's position on the show and make her something other than a walking plot device to read minds.]] This may be explained, however, by the fact that the episode was one of those originally written for ''Star Trek: Phase II'' before that series was scrapped and replaced by the first movie. The original script centered around Lt. Ilia.

* Used in ''Series/DoctorWho''; The newly regenerated Doctor meets the little girl Amelia Pond, who asks to travel in the TARDIS, and the Doctor accepts. Of course, having a little girl around in a show where there's usually at least [[RedShirt one death]] every episode would be a bit dark- and besides, a eight-year-old can't do FanService. So having the Doctor accidentally jump 12 years into the future means that we can now have an all grown up Amy travel with him.
** Doctor Who also has the fastest age-up yet seen. [[spoiler:River Song is introduced as an adult (s04e08) three years before she is born (s06e07) and two years before her parents joined the cast.]]

** In "Babylon Squared" a Starfury pilot passes through the time field around Babylon 4 and dies of old age.
** Inverted with Draal, Delenn's mentor, after he takes control of the Great Machine in "A Voice in the Wilderness". The Machine's life support functions age him ''down'' from a man in his seventies to a man in his forties. However, this was not plot relevant, but rather an excuse for the unavailabilty of the original actor.
** Played straight in "War Without End". Due to having passed through the time field around Babylon 4 back in "Babylon Squared", when the team begins traveling back in time, he rapidly ages. This turns out to be why he couldn't allow Garibaldi to come on the mission.

* ''Series/WandaVision'': Early in the seires, [[spoiler:Wanda]] gives birth to twins, [[spoiler:Billy and Tommy]]. The twins are infants at the start of Episode 5, but quickly age themselves up to become five-year-olds, and later turn ten so they can adopt a puppy. Later in the episode they are about to do it again before their mother stops them.