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[[quoteright:350:[[WesternAnimation/KimPossible http://static.tvtropes.org/pmwiki/pub/images/kim_ar_wiki_6744.png]]]]

->[[MagicMusic Flower, gleam and glow]]
->Let your power shine
->Make the clock reverse
->Bring back what once was mine
->Heal what has been hurt
->Change the Fates' design
->Save what has been lost
->Bring back what once was mine...
->What once was mine
-->--''Disney/{{Tangled}}''

Some form of AppliedPhlebotinum results in one or more main characters regressing to an earlier age. It may be the result of a [[PhlebotinumBreakdown freak accident]], a plot on the part of the bad guys to incapacitate our heroes, or done on purpose so the characters can relive their childhood (at least temporarily).

For some reason this plot is often used in FanFic, where it's called a De-Aging story. Often combined with RaiseHimRightThisTime.

When it's an actual fountain or similar artifact that exists to restore youth, it's a subtrope of {{Immortality}}. These will of course be sought out by {{Immortality Seeker}}s. A downside to this version of the trope is that the fountain is usually stationary and often in a remote region, forcing the newfound immortal to [[WhoWantsToLiveForever permanently stay close to it]] or at least return regularly, and to keep it a secret from others due to ImmortalityImmorality.

When someone dies in his rejuvenated state, expect him to [[NoImmortalInertia turn back old]] immediately.

When a Fountain of Youth effect doesn't get reversed and the younger actor replaces the older one in the cast for good, it's also an example of TheNthDoctor.

It's common for characters to overdo it in stories involving this trope, often winding up as babies, or possibly even regressing out of existence entirely. This may or may not be permanent, but if the character in question was a bad guy, [[RaiseHimRightThisTime expect it to be permanent]]; well, at least, until they grow back up the old-fashioned way. If the character's clothes don't change with them in this event (and it's shown onscreen), it's likely to cause ShapeshiftingExcludesClothing. If the event is offscreen and thus a surprise to the audience or one or more characters, EmptyPilesOfClothing results.

Contrast with OvernightAgeUp and PlotRelevantAgeUp. Compare ReallySevenHundredYearsOld and MerlinSickness. See also HealingSpring.

----
!!Examples:

[[foldercontrol]]

[[folder:Advertisements]]
* In [[http://www.youtube.com/watch?v=mWZYhVNUUUE: this]] advertisement, a young man continues regressing from what may be a high-schooler, all the way down to pre-schooler.
* In a commercial for Nickelodeon in the late 80s, a scientist is trying out a youth potion to make himself a kid again so he can "Kids only weekend". But when he drinks it, he turns into a baby which the announcer says "Sorry babies are too young to watch "Kids only weekend"
* There were a couple commercials for the candy Baby Bottle Pop that featured this trope.
** Whenever kids were eating the candy their heads became that of a baby.
** In one, teens at a dance are bored and eat the candy and anyone who ate one is turned into a cartoon baby.
* In an ad for the PS2, we are shown the aftermath of this. In a nursing home, we see empty halls with discarded clothes with no one in sight. A clock is shown moving backwards and then we see naked babies crawling around.
* In a commercial for Bojangles, an old man shows off his Bojangles box. An old woman isn't impressed and drinks a water fountain to become young again and says "I found the water fountain of youth". We see the man again and he's not impressed. We then see the woman has turned into a girl around 13 and she walks away.
* In a commercial for Johnson and Johnson baby shampoo, we see a woman smiling at the camera and bubbles covering the screen. Everytime this happens she becomes younger from adult to pre teen to child and then to baby.
[[/folder]]

[[folder: Anime & Manga]]
* Happened in ''SketDance'':
** The first time was with Bossun after accidentally drinking Chuu-san's youth potion, mistaking it for a bottle of cola. Himeko [[CutenessProximity absolutely flips over him]].
** The second time was with Himeko and Momoka, several chapters later, at the same time, with the ''same bottle of cola''. Suffice to say, Bossun had a swell time looking after them.
** In the anime, two girls from the student council drink it on purpose, because "life is an adventure". Needless to say, it makes things even harder. In both versions, when the rejuvenated girls drink the antidote, they get ten years older than normal. And of course, by the time the next episode starts,[[UnexplainedRecovery they're back to their normal ages again]].
** Happened for the third time in Chapter 239, with [[TheRival Tsubaki]]. Except this time he reverted both in physical ''and'' mental state. Everyone, including Bossun and Daisy, gushes over [[CutenessProximity how cute he is]].
* Because [[PhlebotinumBreakdown Heaven's computer crashed]], this happened to Urd for about two chapters in the ''Manga/AhMyGoddess'' manga (and one episode of the 2005 animé), with [[OvernightAgeUp the reverse happening]] for youngest sister Skuld. Fortunately, she was able to get an interesting advantage out of it.
* Episode 9 of ''KeroroGunsou'' features mother Aki Hinata getting turned into a teenager by Kururu's newest invention. In a later episode, the same gun turns Fuyuki into a kindergardener. even later, Natsumi, Keroro, Giroro, and Kururu also get zapped by this gun. [[spoiler: In one episode, the entire planet gets zapped by this gun, setting time back by about twenty years.]]
* ''Anime/SailorMoon'' has several examples. In the end of the third season (''Sailor Moon S''), Hotaru, after sacrificing herself to save the world, is brought back as an infant with no memories of her previous life. In the fourth season (''Sailor Moon [=SuperS=]''), [=PallaPalla=] casts a spell on Usagi and Chibiusa that briefly exchange their ages for one episode - causing havoc as Chibiusa, having fulfilled her dream of becoming a beautiful adult, is now unable to summon Pegasus and Sailor Moon can't defeat the Lemures without him. In the beginning of the fifth season (''Sailor Moon Stars''), Hotaru [[PlotRelevantAgeUp rapidly grows back]] as her memories return, and the previous season's BigBad, Nehellenia, is returned to childhood to allow her to relive her life and avoid the mistakes that turned her into a villain in the first place.
** In the [[Manga/SailorMoon manga]], [=PallaPalla=] swaps Usagi and Chibiusa's in the first chapter of the Dream arc, which is actually done to depower the two of them. They eventually overcome it and transform into their proper bodies using their henshin phrases. Later in the same arc, Zirconia depowers both Sailor Moon and Tuxedo Mask in the same manner, turning them into six year olds and preventing them from accessing their magic. Pegasus reverses it by transporting them to Elysion, which has enough purifying power to break the spell.
* The Nehellenia story is reused in ''MermaidMelodyPichiPichiPitch'', but with Michal, the IllGirl and not-quite-villain.
* ''Manga/RanmaOneHalf'':
** Lukkosai, who tried to use the spring of drowned child to regain his youth, but instead just goes from way too old to way too young (both [[MiniatureSeniorCitizens about the same size]]). He then uses this form to get revenge on Happo while pretending to be his own grandson.
** Another story involved mushrooms that change your age in years to their length in centimeters. Ryoga eats a short one and then makes Ranma eat one. They spend most of the chapter trying to change back by growing mushrooms big enough to return them to their normal ages, while constantly sabotaging each others' mushrooms.
** And yet another story from the manga has Happosai feeling the pangs of old age. He finds out about a potion that will restore his youth, but first he needs the tears of a beast that is both male and female. The next thing you know, tear gas and onions fly liberally around Ranma. When he finally succeeds (by poking a pressure point that makes Ranma [[OcularGushers gush out tears like a firehose]]) he trips, and splashes the tears all over the floor. Kasumi wipes them up with a rag, but since it had been used to clean up soy sauce, the resulting potion regresses Happosai's ''mind'' to that of a baby.
* Alessi in Part 3 of ''Manga/JoJosBizarreAdventure'' does this to opponents with his Stand, Sethan. The longer you stand in his shadow (through which Sethan manifests), the younger you get. Unfortunately for Alessi, when he tries this on Jotaro, he learns the hard way Jotaro was {{Badass}} even at age seven.
** It turns even worse out for him in the game when he used it on Joseph. Due to Joseph already being very old, it only regressed him into his late teens. Unfortunately for Alessi, that was the age when Joseph was at his prime and beat the Pillar Men, who were FAR stronger than any Stand users in Part 3. Joseph maintains his youth for a while after beating Alessi, but it eventually wears off and he returns to normal, wishing it could've been permanent.
** In the manga, a young woman was reverted to a ''fetus'' when she had the bad luck of standing in Alessi's shadow for ten seconds (Yeah, it's that fast). Fortunately, she is saved.
* In ''KoiKoi7'', after Yayoi Asuka ([[EyepatchOfPower the one with the eyepatch]]) goes berserk, she's rebooted in one of Otome's spare bodies as a cute young girl named Gantai-chan who doesn't remember much of what happened before.
* In the Dark Tournament arc of ''YuYuHakusho'', an enemy uses a special mist meant to de-age its victims past the point of conception. Unfortunately for him, his target was Kurama, and once his human body went into non-existence, his previous incarnation - full-powered demon Yokokurama - manifested and quickly dispatched him.
* ''RosarioToVampire'' has an example of this one. [[TokenMiniMoe Yukari and Kokoa]], after realizing that they're not being taken seriously due to their age, use some of Yukari's age-up pills for a [[OvernightAgeUp temporary change]]. When the pills wear off, Kokoa finds herself ''younger'' than before. She finds herself in trouble shortly thereafter, only to be saved by the entire UnwantedHarem (sans Tsukune) turned into children along with her. Much cuteness and butt-kicking ensues.
* ''Franchise/DragonBall'':
** King Piccolo and Lord Slug used the titular MacGuffin to restore their youth, putting their power at prime. Roshi and his sister Baba actually drank from a Fountain of Youth, which, rather than restore their youth, fixed them at that age, unable to die from old age.
** Goku turning into a child is part of the whole ''concept'' of ''Anime/DragonBallGT''.
** The concept was used again in the 2013 film ''Anime/DragonBallZBattleOfGods'' where the [[GoldfishPoopGang Pilaf Gang]] were transformed into children off screen.
* Who can ever forget [=APTX-4869=] in ''DetectiveConan''? It regressed Shinichi Kudo and Shiho Miyano's ''body'' by around ten years, causing two {{Teen Genius}}es to live in first graders' bodies. On the other hand, [=APTX-4869=] [[MillionToOneChance is intended to be a poison and is generally successful]].
* In ''Manga/BlackCat'', [[BigBad Creed]] ([[MadScientist Doctor]] did in the anime instead) accidentally shoots Train with a Lucifer bullet, causing Train to transform back into a child (around 8 years old). It only lasts one episode (or a few chapters).
* In ''Manga/MahouSenseiNegima'', WeaselMascot Chamo produces a jar of magical (and illegal) candy that can produce this effect as a sort of illusion (red candy [[OvernightAgeUp for older]], blue for this) both for fun on the part of the girls and as a StrangelyEffectiveDisguise when they [[ClearMyName become wanted people]]. It's been implied that TheMindIsAPlaythingOfTheBody, resulting in the aged-down characters acting with far lower maturity than usual, though they retain their intelligence. This doesn't work both ways, so their [[TheCutie adult forms behave like giddy teens]].
* ''Manga/BlackLagoon'': a non-{{canon}} {{omake}} has the main cast regress to adolescence and, in [[BloodKnight Balalaika's]] case, beyond. For the record, [[TokenMiniMoe loli-Balalaika]] is the cutest thing ever.
** The most shocking ones are Yolanda (the old nun), who was a delicious and ''hot'' [[ChristmasCake cake]] at 29 and Balalaika's underling Boris, who was {{Bishounen}} to the max.
* An ''Franchise/AceAttorney'' doujinshi features Edgeworth turning into a cute little boy thanks to a Fey family recipe gone awry. Given that he was just about to take Wright's place in a case, HilarityEnsues.
* ''IchinenseiNiNacchattara'' has this as part of its core concept, with main character Iori going from high school to elementary school, and getting [[GenderBender gender-bent]] in the process. However, he retains his original personality, and he's not happy about becoming an elementary school girl.
** Later on, [[spoiler: almost the entire town regresses into kids, and judging from the EmptyPilesOfClothing littered all around, possibly even beyond (It's pretty hard to tell)]].
* ''{{Doraemon}}'s NonSerialMovie: Nobita in the Wan-Nyan Spacetime Odyssey'' follows the story of Eiji, an anthropomorphic dog who travels across time to find his ex-owner, Nobita, but the unstable time tunnel causes him to warp into another place and ended up being turned back into an infant. This also happens later with Gian and Suneo, but only temporary.
* In ''Manga/OnePiece'', the supernova Jewelry Bonney's Devil Fruit allows her to change the age of whoever she wants. Guess what she usually does when enemies get in her way?
** From the twelvth movie ''One Piece Film Z'', Ain's Modo Modo no Mi powers allow her to rejuvenate her opponents. Unlike Bonney's powers, however, it works on inanimate objects too, and it can only work backwards, whereas Bonney can also age her opponents. [[spoiler: Nami, Chopper, Robin and Brook all got hit by it, regressing the former two into children, Robin into a teenager, and... not altering Brook's physical appearance at all, [[DemBones since he's a skeleton]].]]
* One of the first monsters in ''Devil & Devil'' is a huge tentacled... thing, that sucks time out of people. It turned a young woman and two young girls into babies, and a third young girl into a child, but they all turned back to normal when it got its ass handed to it by Sword.
* In ''Manga/{{Bleach}}'', [[spoiler: Nel Tu originally had the appearance of a late teenager/young woman, but after being attacked by her rival Nnoitra, she ended up reverting into a small child.]]
* The Korean manhwa series ''Horror Collector'' depicts ElizabethBathory as a young adult who frequently reverts back to her teenage self through her regular {{Blood Bath}}s.
* In ''Anime/{{Stitch}}'', Babyfier (a creature that can turn people into babies) makes 3 appearances.
** In "Rivals stick Together" Babyfier is unleashed at a school turning most of the students and adults into babies.
** In another episode Babyfier turns the main character and her friends into toddlers.
** In the third episode, Babyfier is now good and turns a couple of the villians into babies.
* This is basically the point of ''Mayonaka Lolita'' : Mishiru Kachiwabara, a very beautiful young girl, is given a strange juice by a male student (Aoi Makimura) she had never seen before. As it turns out, that juice is a rejuvenation potion, that their teacher [[WhatAnIdiot had mistakenly given to Aoi as juice]], and Mishiru regresses into a little girl. Her teacher tells her the only way to get back to normal is to kiss the person she loves, but tough luck, Mishiru doesn't love anybody. Because she can't go back home as a child, Aoi brings her to his house and allows her to stay there. [[spoiler: They eventually do kiss at the end of the first chapter, and Michiru turns back to normal... before turning into a child again]].
* In the episode "Ultra Hot Kid's Meal" of ''[[Anime/GalaxyAngel Galaxy Angel A]]'', the Angel Brigade mistakes a Lost Technology for a box of uirō and turn into children, toddlers, and in Milfeulle's case, a baby. Because TheMindIsAPlaythingOfTheBody, the girls gave the twins a pretty hard time looking after them.
* This is part of the premise of ''Manga/AsatteNoHoukou'' : when they both happen to meet at the same time in front of a wishing stone, a young woman transforms into a little girl, and vice-versa. It is implied they change back at the end of the series.
* In an episode of ''AkazukinChacha'', the main trio is tricked by some bad guys into drinking rejuvenation potion, and turn back into babies. Seravy and Dorothy are also reverted to kids. Of course, they all turn back at the end.
* In ''Gakkou Kaidan'' (A Yousuke Takahashi manga that's [[IThoughtItMeant unrelated to the anime]] ''GhostStories''), a VillainousHarlequin transforms a young girl into a baby and a young female teacher into a kid. Both turn back to normal when the harlequin gets his ass kicked.
* ''Marvelous Melmo'': Nine year-old Melmo's magical pills allow her to change her age as she pleases. Depending on the situation, she can change herself into a baby, a nineteen-year old girl, or even regress back into a fetus in order to be reborn as an animal, should she need to.
* In an as-of-yet untranslated chapter of the ''VideoGame/HyperdimensionNeptunia'' manga (Part of said chapter can be seen [[http://visibletime.ararchive.com/_Anim-Hyperdimension_Neptunia2_.jpg here]]), this happens to Nepgear, Rom and Ram, and Uni, who regress into babies after eating some pills that Neptune accidentally gave them. Of course, Neptune has a pretty hard time looking after them, until Gust gave her the pills to change the girls back.
* In an episode of ''BrigadoonMarinAndMelan'', Marine eats some weird chocolate [[MushroomSamba that causes her to start hallucinating]]. Among other things, she imagines herself [[OvernightAgeUp growing into a young adult]], then regressing into a baby.
* A plot used multiple times in ''Franchise/{{Anpanman}}''. A couple episodes have had Baikinman make a spray that changes anyone (or anything) in contact with it into babies (with objects becoming earlier stages, like a tree becoming a sapling). He does this as ways to make Anpanman weak against him, but it always gets foiled in the end. One theatrical short showed there's an entire lake, one side red, which turns the victim into a baby, the other side blue, which returns them to normal. Another theatrical short had Hiyariko, an aspiring scientist, create a potion to make Baikinman stronger...only to turn him into a baby. When he runs off, she makes what she thinks is an antidote, and sprays it all around the town...only to turn the entire town into babies. Thankfully, this potion was only temporary, and everyone returned to normal eventually on their own.
* [[spoiler:Jack Vessalius]] has this happen to him in ''PandoraHearts'' as a result of being rejected by the Abyss. [[spoiler:His soul was shattered to pieces during the fight between Alice, Alyss and the Core of the Abyss. As a result, he kept on de-aging in a cycle:every time he reached the age of twenty-five, he will become younger and younger. Jack's mind has disappeared almost entirely due to a result, leaving only B-rabbit! Oz in place of him, who, according to the manga: "Had lost all of his memories and his powers and fell in a deep slumber." It is unknown at this point if it will happen to Oz since he was in the Abyss for ten years, making him twenty-five, but considering the fact that he himself is a chain, it may or may not happen to him.]]
* ''Manga/TheWorldGodOnlyKnows'': In the "Heart of Jupiter" arc, [[spoiler: Keima is sent back to the past via MentalTimeTravel and given a mission to save a cute but emotionless and mysterious young girl from commiting suicide. If she gets overtaken by despair, she starts getting younger until she's transformed into a baby, which triggers a ResetButton that sends Keima back to the start of the mission. However, he can stop her from getting younger by kissing her before she turns into a baby]].
** Speaking of this manga, it had a three-chapter spinoff called ''Magical Star Kanon 100%'', focused on, as the name implies, Kanon Nakagawa. In it, she is turned into a child by a Runaway Spirit and has to hide her identity and find a way to get back to her true age. The OVA version even has Elsie turn back into a child.
* In ''Manga/DeathNote'', Shinigami can steal the lifespans of humans by writing their names in Death Notes, which kills the human. Humans who use the Death Notes don't get the lifespans of their victims but if a Shinigami uses their Death Note to save a human's life, the Shinigami dies and the human gets all of their lifespan.
* In an episode of ''[[Anime/PrettySammy Magical Project S]], this happens to Sasami as a after-effect of an aging potion. The aging initially works well, but after Sasami returns to her normal age, she turns into a baby overnight.
* In episode 3 ''Manga/MamotteLollipop'', Rokka temporarily transforms Nina into a baby out of jealousy.
* In ''Manga/FairyTail'', [[spoiler: a villain in the Taiyou Village arc named Doriate uses magic that severely weakens people's magical and physical power, and has the added effect of turning them into children. Erza, Natsu and Gray were hit by it, but turned back to normal later. Also, everyone present is regressed briefly in chapter 350 (Including Wendy, who becomes an even younger child)]].
* Some chapters/episodes of ''Manga/ToLoveRu'' and the ''To-Love-Ru Darkness'' OVA feature a creature named the "skunk of youth", which regresses some of the main characters, among others, into kids.
* In ''Manga/MagicalGirlLyricalNanohaVivid'', [[spoiler:one of Fabian's devils]] has a spell that de-ages the target and successfully enchants [[spoiler:[[OneManArmy Sieglinde]]]] with it to incapacitate her.
* ''[[BodyHorror Horiffically]]'' deconstructed in ''Manga/FrankenFran'': The villain from the "Eternal Youth" chapter is an old woman who wishes to regain her youth, but kills many doctors and steals their researches to do so. When comes Fran's turn, it comes back to bite her really hard: [[spoiler: At first, it works and she becomes a young woman again, but because Fran's research was still very experimental, she soon afterwards turns into a pulsating mess of cancer cells.]]
* Amber from ''Anime/DarkerThanBlack'' has this as her [[PowerAtAPrice remuneration]]; she regresses in age every time that she uses her powers. [[spoiler:In the end, she ends up fading into nothingness altogether due to overuse.]]
* ''Manga/{{MAR}}'': Much like the ''Anime/DarkerThanBlack'' example mentioned above, [[spoiler: this is what happens to Loco every time she uses her powers. By the time she's introduced, she looks like a child of around 11 or 12, despite actually being 32 years old. She eventually turns back into a baby after a HeroicSacrifice, and is being taken care of by Chaton and Alan near the end of the series]].
[[/folder]]

[[folder: Card Games]]
* ''TabletopGame/MagicTheGathering'':
** Jhoira from one storyline was exposed to timewarped water that dramatically extended her lifespan after a horrible accident at Urza's Academy. By the events of the Time Spiral storyline,she is over 1000 years old but looks like a 19-year-old--an almost literal fountain of youth.
** Magic has had the literal ''card'' [[http://ww2.wizards.com/gatherer/CardDetails.aspx?id=1715 Fountain of Youth]] for the longest time. Which is how Jodah, Archmage Eternal of the Academy of the Unseen, came to be ''several'' thousand years old by the time he met Jhoira.
[[/folder]]

[[folder: Comic Books]]
* In the first issue of ''Super Hero Squad'' (based off the cartoon of the same name), Dr. Doom plans to use a time machine to go back in time to retrieve the fractal shards. The squadies intervine and the machine malfuctions, turning them all (except for Reptil) into babies (Redwing turns into an egg). Now chaos ensues as the babyfied heroes and villains fight.
* This was a favorite tactic of the extradimensional media mogul Mojo in the Claremont-era ''Comicbook/{{X-Men}}'' comics. Since time passes slowly in comic book universes, this is usually not an issue, as most characters' backstories aren't tied to a specific event. A notable exception is Magneto, a holocaust survivor canonically born in the 1920s. To get around this, he was reduced to infancy and then [[PlotRelevantAgeUp aged back to adulthood]] sometime in the 80s, putting his age firmly back in the traditional comic book "fucked if I know" category. Magneto has naturally gray hair, and was in good physical condition for a man of his age. [[DependingOnTheArtist Different artists]] either draw him as a physically fit older man or a physically fit young man with gray hair.
* TheDCU FifthWeekEvent ''Sins of Youth'' combined Fountain Of Youth and OvernightAgeUp, with a combination of Chaos Magic and an "aging ray" turning all the teenage heroes into adults and all the adult heroes into kids.
* Happens twice from two different sources in ''{{Asterix}} and Obelix All at Sea'': First Obelix gets de-aged as an after effect of drinking the Magic Potion, then our heroes discover the remnant of Atlantis, where everyone is a child (and happy from it) after having drunk from an actual Fountain Of Youth.
* Three of ''TheSmurfs'' were child-ized when Peyo felt he needed a few child characters. There was no cure for the miniaturization, in a rare case where this trope isn't [[ResetButton reset]]. In fact, they didn't mind their new situation.
** However, there were two episodes in the cartoon show where the Smurfs did find a literal fountain of youth that de-aged Papa Smurf and Grandpa Smurf in different situations, both of whom were later restored to their actual ages.
** And there's "Smurf Van Winkle", where the other Smurfs try to pull a RipVanWinkle on Lazy to make him think he has slept for a few centuries while his fellow Smurfs have aged incredibly. Lazy works on a potion to bring them back to the same physical age he is, but the whole thing was revealed to be a ruse when they were all de-aged into Smurflings.
* ComicBook/RasAlGhul's Lazarus pits. While not -exactly- the same thing, the pits are used at one point in ''WesternAnimation/BatmanBeyond'' to restore elderly Bruce Wayne back down to his 40's (as part of a Ra's plot to put his mind into Bruce's body).
** There was another story from the 60's in which Batman is turned into a toddler but he retains his intelligence and strength.
* JudgeDredd, a rare example of a comic book character who ages in real time, had a couple of decades taken off in the 1990s after being exiled from the city and getting his face burnt off.
** Within the comic, there's stookie capsules, which dramatically slow the ageing process in humans. Since producing them requires the slaughter of a peaceful and harmless alien species, they are highly illegal.
* In ''TheIncredibleHercules'', Zeus gets reverted back to childhood, both physically and mentally, by drinking from the river Lethe.
* In a "Gnuff" story in the {{Furry|Fandom}} series ''Critters'', the main characters are stranded on an island divided by a steep mountain range where one side has water that makes you younger and the other has potatoes that make older. So, if you're living off the land on that island, you need to balance these foodstuffs to maintain your true age. Unfortunately, the one pass through the mountain range gets blocked and the characters on both sides realize that they are in terrible danger of eventually overbalancing on one of the materials and dying or disappearing as a result unless they can each get to the other side. [[note]]This story, done by Danish writer/artist Freddy Milton, has a long and strange background, and has no less than four versions going around with wildly different main characters. It was was originally made as a DonaldDuck story, but wasn't found worthy for publication, so Milton -- who had the right to the story but not the characters -- redrew it with his own CaptainErsatz characters who were geese instead of ducks. Later still, when drawing comics for the Scandinavian WoodyWoodpecker magazine, he redid and expanded the story with Woody and his niece and nephew Knothead and Splinter taking the roles of Donald and the boys. Finally, he redrew the story ''again'' as a "Gnuff" story, and this was the version that was published in ''Critters.'' You can find both the Donald Duck version ("The Big Sneeze") and the Gnuff version ("Gargantua's Cure") of the story in the "English Stuff" section of [[http://www.freddymilton.dk/ Milton's official homepage.[[/note]]
* One ''{{Popeye}}'' adventure involved a search for the Pool of Youth. While the pool doesn't actually make you physically younger, it extends your lifespan indefinitely, and gives you a younger mentality- a man claimed to be over 200, but felt he was 6. The Pool was guarded by the Sea Hag's sister, and her army of cavemen.
* Mina Murray and Alan Quartermain search for the Fire of Eternal Life in ''TheLeagueOfExtraordinaryGentlemen New Traveller's Almanac''. They fail to find it, and Alan [[FakingTheDead dies]] on the trip. After an indecently short period of time, Mina hooks up with [[MyGrandsonMyself Alan Quartermain Jr]]. [[SuspiciouslySpecificDenial Really, that's what happened]]. [[BlatantLies It's in the Almanac]].
* In TheDCU, the Fountain of Youth is what gave Detective Chimp the ability to speak to other animals and stopped his aging. It's either [[DependingOnTheWriter magical, radioactive or alien nanotechnology.]]
* In the story "A-Corny Story", in issue #28 of ''Tales from the Crypt'', this guy who was fired by his late boss' son for being "too old" sent him a tree from Haiti that was supposed to prevent old age. It started out as this hideously gnarled specimen that kept growing younger, and its new owner started doing the same. On the day the tree finally de-aged into a seed, the guy de-aged into a sperm cell or something and vanished.
* ''ComicBook/SpirouAndFantasio'' had the main characters search for the actual fountain. After the [[spoiler: mission ended in failure with the water losing its power permanently]], Spirou [[BreakingTheFourthWall winks]] and says [[spoiler:[[ComicBookTime Do you really think we need that?]]]]
* Several ''Disney'' comics featured either the fountain itself, or characters getting younger. For an example, in the story "History re-Petes itself", Pete's attempt to turn Mickey into a baby backfires, resulting in Mickey trying to RaiseHimRightThisTime. Over the two weeks Pete grows up rapidly, Mickey and his friends attempt to make him into a good guy, but infortunately, as you might have guessed from the title, it fails and Pete remains bad.
* The Franco-Belgian comic ''Les Petits Hommes'' features a story named "Miss Persil". It centers around a young girl who has the mind and personality of a five-year old, due to entering a coma at that age and miraculously waking up recently. It obviously causes a lot of problems, especially considering her parents intend to place her in a school in the "big world", but the Doctor finds a way to get around that by making her drink an elixir of youth to rejuvenate her, so that her body will match her mind. It works well, but HilarityEnsues when she actually takes the elixir with her.
* One ''Franchise/{{Batman}}'' comic features a group of mad scientist villains who turn Batman into a toddler in order to make him more vulnerable. Yet he still keeps his adult mind, memories, and strength and skills. So pretty much all they did was make him a harder target.
* The fountain appears in the MarvelUniverse in both the original Man-Thing series as well as the first She-Hulk series, with a small village of people from the Conquistador days living there. Drinking the water however isn't what leaves one immortal but regularly bathing in it (drinking it will leave one a shriveled, red-skinned immortal). She-Hulk eventually convinces them to destroy the titular fountain as they've also grown apathetic (when several villagers are killed by wild beasts they ignore it) as strong emotions break the immortality causing one to begin to age again since they've given up living by what they've sacrificed for immortality.
[[/folder]]

[[folder:Fan Works]]
* In ''Fanfic/KyonBigDamnHero'', Nagato provides this function for Kyon, Mikuru, and Kanae. Otherwise the [[spoiler: YearInsideHourOutside training]] would make them age by over a year every night.
* In ''Fanfic/WithStringsAttached'', the four awaken to find themselves on another planet and 16 years younger—their 1980 minds in 1964-age bodies. They think they've been geuninely de-aged, but at the end they find out they're in cloned bodies. The Fans wanted to give them fresh new bodies as payment for going through all the hassle on the planet; they were going to age the bodies, give them appropriate scars, etc., after the adventure was over. However, things got out of hand, and a whole lot of magic got dumped on the clone bodies. Because the Earth universe has no magic, this meant that the four had to be transferred back to their original bodies in order to return home.
* The [[ExactlyWhatItSaysOnTheTin Youth Restoration Spell]] from ''Fanfic/MyLittleAlicorn'' reverts any pony it's used on to any prior age for two hours, after which they are ''supposed'' to turn back to normal. Naturally, Luna thought it would be a great idea to use it on Celestia as a prank, not realizing that [[ModeLock it works a little bit differently on Alicorns.]] HilarityEnsues.
* The ''StarTrekTheOriginalSeries'' fics ''FanFic/{{Insontis}}'' and ''Fanfic/InsontisII'' detail this happening to Kirk and Spock, respectively. HilarityEnsues.
* The ''FanFic/FacingTheFutureSeries'' features a story where [[spoiler:Danny and Sam revert to five year olds in homage to a ''Series/StarTrekTheNextGeneration'' episode entitled "Rascals"]].
* Happens to Data in [[http://archiveofourown.org/works/765803 "Small Packages]] by [[http://archiveofourown.org/users/RebeccaOTool/pseuds/RebeccaOTool RebeccaOTool]], via an unoccupied android body left by his late father. Played for laughs. At first.
** The same author gives us [[http://www.fanfiction.net/s/2543741/1/Changes Changes]], where Egon of ''WesternAnimation/TheRealGhostbusters'' is turned into a child due to an experiment gone awry. The [[spoiler: nightmare]] sequence where he de-ages into nothingness [[AndIMustScream while screaming for help from his uncomprehending teamates]] is chilling.
** Also happens to House and Wilson [[http://archiveofourown.org/works/770714 Monkey's Paw Syndrome]] due to magic. MakesSenseInContext.
* Loki turns the Avengers [[spoiler: and himself accidentally]] into toddlers in [[http://archiveofourown.org/works/767023 this story]]. Unlike most others in this genre, the children retain their memories and powers, leading to more than the usual BadlyBatteredBabysitter plot.
* Loki [[http://archiveofourown.org/works/773579 changes himself into a four year old]] semi-voluntarily, but due to [[PowerNullifier exhaustion]] he can't change back. He [[OlderThanTheyLook retains his memories and personality]], and decides to use his new situation...
* ''FanFic/GettingBackOnYourHooves'': This is what Poison Joke does to Trixie. Interestingly, it also affects her mentally (and since she didn't have a happy childhood...)
* The [[Fanfic/LifeInManehattan Manehattanverse]] story "Fillie's Play" focuses on this, as a magical mishap during one of Twilight's experiments turns her and the rest of the Manehattan 6 back into fillies. [[spoiler: And has the [[PlotRelevantAgeUp opposite]] effect on Orange Sherbet's daughter, Tangerine.]]
* Twilight accidentally turns herself into a filly in ''FanFic/DiariesOfAMadman'', after one of her spells backfires.
[[/folder]]

[[folder:Film]]
* The MacGuffin weapon of the BigBad in ''SkyHigh'' did exactly this.
* The titular character in ''Film/TheCuriousCaseOfBenjaminButton'' has a similar problem: he ages backwards. He is born as an old man, and dies of old age as an infant.
* ''Film/TheFountain'' involves a [[FramingDevice story within a story]] about a Conquistador's [[TheQuest quest]] for the Tree of Life, which can theoretically grant immortality. Outside the frame, there is a tree which essentially de-ages a cancer-ridden monkey and presumably grants immortality to the main character.
* This is the point of ''SeventeenAgain''.
** Also the plot of the very early made-for-tv Creator/KeanuReeves movie ''Young Again'', from which ''SeventeenAgain'' seems to be ''heavily'' drawn. ''17 Again'' is practically an unoffical(?) remake of the film.
* The SequelHook at the end of ''Film/PiratesOfTheCaribbean: At World's End'' ends with (the immortality-seeking) Jack unfolding a map to something called the "Agua De Vida". The book that the next movie is based on revolves around the Fountain, so...
** [[spoiler:The Fountain in ''On Stranger Tides'' is played with. It doesn't make you any younger, but instead adds years to your life. However you need someone to take the years from...]]
* The MacGuffin in ''TheNuttyProfessor 2''. Professor Sherman Klump creates a fountain of youth formula which lasts temporarily.
* In Film/TheThreeStooges short "[[http://threestoogespictures.info/all-gummed-up/ All Gummed Up]]", the boys are druggists who invent a youth serum and give it to their elderly landlord's abused wife. Predictably, she turns into a beautiful young woman. But when the landlord tries it, he turns into a bawling infant.
** In the remake "Bubble Trouble", the landlord turns into a gorilla.
* Beautifully played with in the finale of the [=IMAX=] short ''Film/CirqueDuSoleilJourneyOfMan'': When TheEveryman middle-aged hero accepts the old bowler hat of his youth from a little Vagabond Girl and ducks offscreen so she can put it on him, the voiceover narration explains "Years turned to dust. I was young again." [[spoiler: He rises back into frame as an ''old'' man but it's clear he's as full of life and joy as he's ever been, having regained his youthful spirit, making this an example of this trope and Overnight Age Up all at once!]]
* The pool house in the movie ''{{Cocoon}}'', by way of [[AppliedPhlebotinum Alien Phlebotinum]].
* The planet Baku in ''Film/StarTrekInsurrection''. The fact that it remains unused by the rest of the Federation and is only used by the Baku makes it seem much like a [[HiddenElfVillage Not So Hidden Elf Village]]
* Smurf essence becomes this in ''Film/TheSmurfs'' when Gargamel used it on Odile's mother, which makes Odile want to get her hands on it.
* Early on in the French film ''Film/LesVisiteurs'', a witch forces an old woman to drink one of her potions. This causes her to inflate slightly and rocket through the roof (And judging from the other holes in the roof, she wasn't the first victim), only to fall back in the house a minute later, as a younger woman.
* In ''[[{{Film/Wishmaster}} Wishmaster 2]]'', one of the burglars who broke into a museum meets the Djinn, who grants him one wish. The burglar, scared out of his wits, wishes [[ExactWords he were never born]]. The poor guy really should have known better than to ask that of a JackassGenie. The Djinn is all too eager to grant his wish, causing the guy to age backwards until he flat out disappears, [[EmptyPilesOfClothing only leaving his clothes behind]].
* ''Film/SurLaPisteDuMarsupilami'': A special orchid's juice can be distillated into a youth potion. The Marsupilami being apparently linked to those orchids, the BigBad is after it. [[spoiler: He eventually gets his youth back, [[RaiseHimRightThisTime plus interest]].]]
[[/folder]]

[[folder:Literature]]
* In Creator/DianaWynneJones' ''Literature/HouseOfManyWays'', the grown wizard [[Literature/HowlsMovingCastle Howl]] became the DeliberatelyCuteChild Twinkle partly as a disguise and partly (he said) because he felt he deserved a better childhood than the one he'd actually had.
* Creator/TerryPratchett did this in ''Discworld/TheLastContinent'', combined with OvernightAgeUp, when the wizards travel to a place (Fourecks), where, due to morphic instability, Ponder Stibbons becomes an eighty-year-old, and the Dean becomes a thirteen-year-old. And then there's [[IWasQuiteALooker Mrs. Whitlow...]]It wears off within a few minutes.
** And in ''Discworld/{{Eric}}'' Ponce da Quirm is an old man who's spent his entire life searching for the Fountain of Youth. Rincewind doesn't quite have the nerve to ask him whether it would have been better to just have a life in the first place. When they later encounter him in Hell, they learn that he did find it, but there's one thing all the legends forgot to mention about the water of the fountain of youth - boil it first.
* K.H. Metzger's ''Skye Sparkler'' is all about this. A woman in her thirties designs a little-girl superhero character and [[BeCarefulWhatYouWishFor subsequently, permanently becomes her]].
* In ''The Thief Lord'' by Cornelia Funke, there is an example of this trope in the form of [[spoiler: the elderly Conte and Contessa, who use a magical merry-go-round to become children again]].
* In the ''Literature/{{Blackcollar}}'' books by TimothyZahn, a drug called Idunine can reverse many of the effects of aging. In fact, taking heavy doses of it is once used to disguise several characters, as they now look much younger.
* In Creator/RobertAHeinlein's Future History series, medical rejuvenation therapy works to reverse the aging process through a variety of techniques, from swapping the body's entire blood supply to cloned tissue transplants. In extreme cases, a human at near-death can be completely rebuilt to look and feel [[ReallySevenHundredYearsOld twenty years old]] again, complete with a fresh brain that's had the memories from the old one [[BrainUploading copied into it]]. This plus a program of applied eugenics designed to extend the natural lifespan has resulted in a subrace of near-immortals, of whom Lazarus Long (featured in ''Literature/TimeEnoughForLove'' and ''Literature/TheNumberOfTheBeast'') is by far the oldest.
** ''Literature/GloryRoad'', while set in a different continuity than the Future History series, also features medical rejuvenation, known on Center as "Long Life" treatment.
* In ''[[Literature/GarrettPI Gilded Latten Bones]]'', [[spoiler: the King of Karenta is discovered to be shielding a trio of necromancers who have been keeping him and themselves unnaturally young]]. Unlike most examples, users of this age-reversal effect retain their gray hair, so must wear wigs to suit their youthful bodies.
* The Rapture becomes this for older Christians in the ''Literature/LeftBehind'' book series when they receive their glorified bodies, while for children and teenagers it brings them up to the same age level as the adult believers. At the end of the Millennium, even the longest-lived naturals (who are at that point all believers) are restored to the prime of their youth.
* Willy Wonka invented Wonka-Vite, a invention that makes people younger. It's used in ''Literature/CharlieAndTheGreatGlassElevator'' on Charlie's three still-bedridden grandparents. Unfortunately, they don't listen to his instructions and take too many -- one pill takes 20 years off, and each takes four pills. That renders two of them babies, and since Grandma Georgina was ''seventy-eight'' and thus becomes negative two years old, her spirit winds up in the dreary Minusland. Luckily, Mr. Wonka also created a RapidAging counterpart, Vita-Wonk...
* Due to a quirk in their physiology, the Cheela in ''Literature/DragonsEgg'' can rejuvenate. Under particular conditions, when their body has been battered enough, it will revert to [[PlantAliens the plant the Cheela evolved from]] and heal itself, [[RipVanWinkle taking the best part of a lifetime]][[note]]About half an hour -- the Cheela [[YearInsideHourOutside live on a different time frame]][[/note]] than us in the process. Then the plant turns back into a Cheela in its prime. In the sequel, ''Starquake'', this very rare and risky process has been harnessed and rejuvenation machines are in use.
* The carousel in ''Literature/SomethingWickedThisWayComes'' can function as either this or as an OvernightAgeUp, depending on whether it runs backwards or forwards. Carnival co-owner Cooger uses it to go incognito as a preteen boy.
* A literal fountain drives the plot of ''Literature/DirgeForPresterJohn''. It's nothing like what the characters expected it to be, but it does the trick.
* In ''Literature/TalesOfKolmar'', lansip leaves and fruit, very difficult to get to and already a potent {{Panacea}}, can be distilled into a liquor which can make the drinker younger. There's a tale about an elderly merchant who was found after drinking an overdose, with the body of someone in his twenties. Berys is much more careful with his supply, taking a little at a time and prudently using [[WeWillNotUseStageMakeUpInTheFuture makeup]] to make himself still look old, and arrives at midtwenties without dying of it.
* ''Literature/HarryPotterAndTheOrderOfThePhoenix'': During the battle of the Department of Mysteries a Death Eater's head turns into that of a baby when he falls into a magical clock.
* On one of the unknown islands visited by Máel Dúin and his companions in the medieval Irish ''[[Literature/TheVoyageOfMaelDuin Voyage of Máel Dúin]]'', the voyagers observe a giant bird rejuvenating itself by bathing in a magical lake. Diuran the Rhymer tries it too and emerges permanently rejuvenated.
* In ''Literature/MistbornTheOriginalTrilogy'', The Lord Ruler pulls this off by being both an Allomancer and a Feruchemist. To elaborate, Feruchemists can store youth in the metal atium, which causes them to look and feel older than they really are for a time in exchange for allowing them to look and feel younger than they really are for the same amount of time later on. Allomancers can "burn", or Allomantically metabolize, various metals to gain specific superpowers: tin grants SuperSenses, brass allows you to dampen someone's emotions, etc. The Lord Ruler discovered that if you burn Feruchemically charged metal you get back ten times the Feruchemical charge you put in. Effectively, the Lord Ruler had an infinite supply of youth.
[[/folder]]

[[folder: Live Action TV]]
* The ''Series/BuffyTheVampireSlayer'' episode "Band Candy", in which all of the adults ingested chocolate bars that had spells inside of them that did not physically de-age the characters, but made them act as they had as teenagers. The episode is filled with hilarious examples of the Scoobies becoming more and more horrified by their parents, teachers, and even the stodgy Giles, as they act in irresponsible and (in the case of Giles) criminal ways.
* ''Series/StarTrekTheNextGeneration'':
** The episode "Rascals", in which a transporter malfunction turns Picard, Keiko, Ro and Guinan into children, during which time the ''Enterprise'' is captured by hostile aliens. Despite the fact that they clearly keep their adult minds, they still have to save the day using childlike cleverness rather than their usual methods. As children, they would lack the strength and speed to do many of the physical actions an adult could perform.
** The episode "Too Short A Season" has an old Admiral who must negotiate a hostage situation. He seems to have taken a drink from this Fountain as he keeps getting younger. We find out [[spoiler: he takes an alien drug that does this too well---the strain on his body kills him.]]
* One of the few permanent examples comes from ''Series/KamenRiderDenO'' which did this out of necessity. The actress who played female lead Hana quit unexpectedly in the middle of the series, but her character was too important to the story to write out. So the producers replaced the twentysomething actress with an eight-year-old. A subplot was added in which Hana was de-aged due to a time anomaly...and stayed that way. In a further subversion, none of the characters, including Hana herself, seemed to have much of a problem with this, and hardly any effort was made to find a cure. After the third movie, the show's star moved on to other projects, and thus this happened to protagonist Ryotaro as well. In this case, however, they simply brought back the actor who played the preteen version of him from the first film. It's given a HandWave when he remarks that this sort of thing happens on occasion when you mess around with time travel, which may also explain why there hasn't been a mad scramble for a cure for either him or Hana.
* ''MightyMorphinPowerRangers'':
** The ''Alien Rangers'' half-season was an extended plot-arc in which all the regular characters were age-regressed to young children.
** This happened in a season 2 episode. In both cases, it seemed to be a strange mix of this and TimeTravel- all the high-school-age heroes were now in elementary school, but they had the same teachers and principal. All the characters who were originally from out of town were still there as well.
* A mild example happens in ''Series/StargateAtlantis'', when Sheppard's tenuous Wraith ally returned the years he had, um, borrowed, plus a bit. Possibly an attempt to balance out the six months he spent in a time dilation field.
* ''Series/StargateSG1'':
** The Goa'uld Sarcophagi can greatly extend life as well as healing wounds (but at the cost of negative psychological effects). However, this isn't that important to the Goa'uld, as they can just take another human host anyway. Though as Lord Yu demonstrates Goa'uld symbiotes age and go senile on their own, and without the sarcophogus have a lifespan of about two hundred years.
** This appears to be the case when 15-year-old O'Neill shows up in the episode "Fragile Balance." [[spoiler: In actuality, he was an Asgard-designed clone that did not mature properly.]]
* ''Series/TheMightyBoosh'': In the episode, "Fountain of Youth," Howard and Vince visit Naboo's home planet, Xooberon, in search of their own Fountain of Youth, but the Hitcher is looking for it, too. HilarityEnsues.
* ''Series/DoctorWho'':
** "The Time Monster" has Sergeant Benton temporally regressed to babyhood by a time-eating monster. He is eventually returned to adulthood, in front of everybody else, stark naked. HilarityEnsues.
** In "Boom Town," Blon Fel-Fotch Pasameer-Day Slitheen is a member of the Slitheen family of the alien Raxacoricofallapatorian species. In the episode, is it explained that members of the family are raised from infancy to be sociopathic criminals. When Blon is exposed to the Heart of the Tardis, it turns her into an egg; she will be returned to her planet's nurseries, where she will have a chance for a new life.
** "The Lazarus Experiment" episode is about the titular scientist inventing a device that restores cells to a previous state. Being an old man, he tries it on himself first, becoming young. That is until the horrible side effects of the device are discovered. The [[EvilCounterpart Master]] later uses the technology in reverse to make the Doctor old.
* Happened in ''Series/TheGenieFromDownUnder'', where Penelope, after abusing her long-suffering Genie, Bruce, with over 200 wishes in an hour, [[JackassGenie he intentionally made a wish of hers backfire]], turning her into a baby. Oddly though, due to the nature of the wish, nobody seemed to be surprised by her age regression, as though she was supposed to be an infant.
* At the end of the 1998 ''Film/{{Merlin}}'' series, when the titular character is a CoolOldGuy complete with beard, [[spoiler: his last act of magic is to restore the youth of himself and his love, returning them to their younger personas seen years earlier in the story.]]
* In ''Series/{{Sanctuary}}'', all of The Five had unnaturally long lifespans [[spoiler:due to the infusion of pure vampire blood with the exception of Watson who was implied to have long life due to a technological device he created (as a result of his increased intelligence due to the aforementioned vampire blood (Aquifer Of Youth?))]] Except for [[spoiler:Griffin, the [[{{Invisibility}} Invisible Man]]]].
* ''Series/TheTwilightZone'':
** In episode "A Short Drink From A Certain Fountain" has an old man try to regain his youth to keep up with his trophy wife. His scientist brother has found an anti-aging serum, but it's untested... [[spoiler:The serum reduces him to infancy. As his wife is about to walk out, his brother (who now controls the man's estate) stops her, informing her that if she wants to keep one penny of her infant husband's money, she'll have to raise him back to adulthood...]]
** In the episode "Kick the Can", all but one of the residents of an old-age home became kids again by playing the titular game.
* In the children's series ''Series/LazyTown'' it occurs in the episode "Little Sportacus" where Sportacus is de-aged by Robbie Rotten's machine. This episode shows Sportacus being just as active and agile as his adult self and sends the message to kids that its never too early and children no matter how young are capable of amazing things.
* The protagonists of ''Series/TheLegendOfDickAndDom'' stumble onto the Fountain of Youth (or fall into the Muddy Puddle Of Youth, anyway) and are regressed to childhood just in time to meet a bunch of witches who... ''really like'' [[ToServeMan children]]. [[spoiler: Naturally, the witches end up falling in themselves by the end.]]
* In episode 16 of an old Sentai series called ''KyodaiKenByclosser'', the villains use a weird gun to revert a couple of children (Yeah, children, strangely enough) to infancy, before turning them into old people with another gun. A young woman is also regressed into a baby. Obviously, all of them are eventually turned back to normal.
* A short-lived late-70s sitcom called ''Big John, Little John'' was about this guy who, having unwittingly taken a sip from the Fountain of Youth, was prone to turning into a twelve-year-old at inconvenient times.
* An episode of ''Series/SirArthurConanDoylesTheLostWorld'' had the gang meet a woman with water from the fountain of youth. [[spoiler: Unfortunately, her supply runs out and she reverts to her true age and dies]]. Professor Challenger drinks a little of the water, and while it doesn't make him look younger, it heals his wounds and makes him temporarily strong, agile, and energetic like a teenager.
* On an episode of ''{{Series/Smallville}}'', an old man takes a spill into the koi pond at his retirement home, which turns out to be lined with GreenRocks that make him physically 50 years younger. Unfortunately, he turns out to be a {{sociopath}} with a long list of scores to settle, one of which is against the Kent family.
* ''Series/OnceUponATime:'' [[spoiler:August has turned back into a young Pinocchio]], probably permanently.
* In ''Series/{{Charmed}}'', one is being guarded by nymphs, but is really more of a HealingSpring. Another one shows up, and this one actually looks like a stone fountain. Irritatingly enough, Piper says "But that's just a myth!" when confronted with the second one, even after having come across the first one, possibly because she and her sisters had promised the nymphs from the first fountain that they would keep its existance a secret.
* A short-lived live-action Saturday Morning show from the 80s dealt with a scientist who found and drank from the fountain so suffered from random bouts of deaging to a pre-teen and back again (naturally played for the troubles it caused as he was forced to become a school teacher so he could pretend to be his son when de-aged and a student).
* In ''Series/TheOuterLimits'' revival episode "The Last Supper", an elderly scientist is tracking an immortal woman in the hopes that her blood will restore his youth. After all, he tried it on his (literal) guinea pig the last time he had her in custody and it's been alive for decades. In his desperation, however, he doesn't think his plan through and just scales up the dosage relative to body mass. He gets his youth, [[KarmicDeath plus interest]].
* In ''Series/TheFlyingCestmir'', Cestmir gains seeds for six magical flowers. One of them causes people to de-age for a certain period of time until the effects wear off. The old professor uses it, but apparently nobody else does.
[[/folder]]

[[folder: Newspaper Comics]]
* In a recent strip for ''{{Lio}}'' Lio uses a time machine to go to the beginning. As a result he is sent back to the womb.
* One time in ''ComicStrip/JumpStart''. Marcy and Joe are buying noth their infant twins a toy. They comment that because they have twins they have to buy two of everything. They then mention they have four kids, the next panel shows them, their two older kids as babies. The same age as the twins. They then comment they are a family of sextuplets.
* One Creator/CharlesAddams cartoon shows a group of children standing next to a fountain in a jungle, all holding metal cups and dressed as Spanish conquistadors. One of them is saying "So, great. We found the Fountain of Youth. Who's gonna sail the old tub back?"
[[/folder]]

[[folder:Theater]]
* The finale of the early Creator/CirqueDuSoleil show ''Theatre/NouvelleExperience'' had the inhabitants of a MagicalLand change [[spoiler: TheEveryman hero]] back into a child.
[[/folder]]

[[folder: Video Games]]
* ''VideoGame/{{Civilization}} V'' features a Fountain of Youth as a World Wonder. All units that move adjacent to it gain the Double Healing promotion for free.
* Gilgamesh from ''[[VisualNovel/FateHollowAtaraxia Fate/hollow ataraxia]]'' did this with a youth potion because, apparently, "this whole mess is stupid, screw you all". All the more hilarious, considering that he's been a tyrant (in the past), not to mention a [[KickTheDog dog-kicking]] KnightTemplar and BigBad who wanted to [[spoiler:unleash a terrible curse on humanity because only those who could survive it were worthy of being ruled over]]; when he reverts, he turns into a cute little boy that everyone loves.
* A fountain of youth is present on Easter Island in the ''VideoGame/SamAndMaxFreelancePolice'' game ''Moai Better Blues'', the reason that the island is populated by babies.
* In ''VideoGame/TheCurseOfMonkeyIsland'', Guybrush is age-regressed to the form of a young child when he is trapped in the [[CircusOfFear Carnival of the Damned]] by Lechuck. This also happens to him at the end of Money Island 2: Lechucks Revenge, but is actually an illusion to trick him rather than physical.
* In ''VideoGame/BrainLord'', in the second magic shop you come across, you find it is run by three old women. If you go in the kitchen and talk to the old women there, she'll offer to let you try a new youth potion. Drink it, and instead of you being youthened, all three of the elderly women change to teenagers.
* The Golden Suit in ''HenryHatsworthInThePuzzlingAdventure'' grants youth to whoever wears it. Henry's in his sixties/seventies, so when he dons it, he is restored to young adulthood. [[spoiler:Cole, unfortunately, is only ten or so - so when he dons it in TheStinger, he's reduced to infancy.]]
* The "Babality" {{finishing move}}s in the ''MortalKombat'' games, in which the victor would somehow turn the loser into an infant.
** Seeing as how this is a franchise known for its violence, programmers wisely fixed it so the winning player lost control of their character the instant their opponent became a baby; the victor would immediately go into their win pose. The idea behind the babalities was to provide a more innocent alternative to the infamous fatalities. Unfortunately, a glitch was later discovered that, when exploited, allowed you to viciously attack the baby.
** Despite being unpopular to most fans of the series, the finishing move made a return in the 2011 game "Mortal Kombat". This time instead of the opponent turning into a baby and sitting while crying, the babified opponent would now do a funny animation relating to them. In fact now, even the bosses can have a babality done on them.
* in ''{{Drakengard}}'', everyone who make a pact with a creature has to sacrifice something. Seere sacrificed his "time", which meant that he'd never age, and never grow up. This would possibly be considered CursedWithAwesome except Seere is ''six'' and will be so for his whole life. The fact that he's travelling with a pedophile and a cannibalistic elf with a specific taste for children does not help in the least.
* At the end of ''VideoGame/EmeraldCityConfidential'', [[spoiler:Petra deliberately does this to William to [[SetRightWhatOnceWentWrong save him from life imprisonment and his memories of having been]] a [[TheFairFolk Phanfasm]] [[TheMole spy]]]].
* Borf's weapon in the full-motion video game ''{{VideoGame/Space Ace}}'' turns people into infants. He had already used it on the main character, which turned him into a rather weak teenager, but at certain points in the game the player can temporarily restore Space Ace to his proper age. And of course, he ends up being HoistByHisOwnPetard.
* In the ''VideoGame/KingsQuest'' series, there have been 2 cases of this trope.
** In ''[[VideoGame/KingsQuestIIRomancingTheThrone King's Quest II +: Romancing the Stones]]'' you will stumble upon a youth potion. If you drink it, you will turn into a baby and it will be game over. At the end if you give it to the villain she will become a young woman again (good or bad depends on what you do).
** In ''KingsQuestVIIThePrincelessBride'', the female villain is turned into a baby.
* In ''VisualNovel/RadicalDreamers'', this is an important plot point: [[spoiler: Kid is revealed to be Schala from [[VideoGame/ChronoTrigger the previous game]]: After the Ocean Palace incident, she was overcome by grief and guilt over what her actions had caused. The Frozen Flame picked up on those emotions, and responded by transforming her into a baby, erasing her memories, and sending her to the modern era, where Lucca found her and raised her]]. Granted, this game is not canon anymore, but an easter egg from ''VideoGame/ChronoCross'' implies that the events of ''Radical Dreamers'' actually happened in another dimension.
* In ''MaiHime Fuuka Taisen'', Yukariko's Child turns her opponents into young children.
* [[VideoGame/TheSims The Sims 2]] had the Elixir of Life Aspiration reward, and the "milk" produced by the cowplant available in the ''University'' expansion after it eats a sim, which is a more potent version (making a sim 5 days younger per dose rather than three). The ''Generations'' expansion for the third game added the "Young Again" reward, which is ExactlyWhatItSaysOnTheTin, and the Age Freeze reward, which is also ExactlyWhatItSaysOnTheTin.
* In the recent ''{{Tekken}}'' games starting from ''Tag 2'', Heihachi Mishima has found a way to rejuvenate himself back to his prime thanks to a serum made from Ogre's blood. This change has only shown in non-canon games so far, but given that it was induced by Creator/DaisukeGouri's [[RealLifeWritesThePlot unfortunate suicide]], it's likely to stick to the canon series as well.
* In ''VideoGame/MagicalDrop 3'', the FinalBoss Wheel of Fortune is sent back to the past and transformed into a baby after she is defeated.
[[/folder]]

[[folder:Webcomics]]
* In ''Webcomic/{{Opplopolis}}'' during Luke Dugans' interview with Shirley Kidd about a mysterious movie she appeared in called ''Marvedyne'' (that word being the series' MacGuffin), the latter [[http://www.opplopolis.com/issues/4/5 suddenly de-ages]] from 60-ish to 20-ish with thus far [[LeftHanging no explanation]], though there was a [[SlippingAMickey conspicuous cup of coffee]] earlier in the scene.
* When Mingmei in ''Webcomic/TheWotch'' discovers that she used to be Dr. Sorgaz, everyone assumes that she would want to be turned back… except the Sorgaz persona himself, who basically takes it as a second chance in life, and instead opts to merge with Mingmei permanently.
** Not to mention 21-year-old Evan's frequent temporary escapes into a 4-year-old ([[GenderBender female]]) body, called "Lily".
** Seriously, what about the entirety of ''Adventures in Babysitting''? Even though Evan turns into an adult female, Anne, Robin (Robyn?), and Jason were turned into children (Okay, they turned into the opposite gender too, but that hardly matters!)
* Emily from ''Webcomic/{{Misfile}}'' suffers from this, though she was only regressed by two years rather than the usually much larger amount. Since she was just about to turn 18 and had received her acceptance letter from Harvard these were a rather vital couple of years though.
* In one strip of ''Webcomic/AxisPowersHetalia'', England de-ages Korea to make him less annoying. In a later April Fool's Day event he does it again to France.
* ''Webcomic/TheDragonDoctors'':
** A team of magical robbers are trying to steal a large drum of rejuvenating fluid in the "Thieves of Life" arc. An acid booby trap cracks open the drum, however, exposing one of the thieves to an overdose of the fluid, immediately transforming her into a baby.
** A {{Backstory}} chapter features a [[http://www.drunkduck.com/The_Dragon_Doctors/index.php?p=773779 lake of youth]] that is responsible for the 'deaths' of several colonists. It's basically a {{Deconstruction}} of the Fountain of Youth: the lake is hidden because everyone who goes near it dies. Nothing grows around it because it causes everything to un-grow, so it's a desolate wasteland. Even contact with the vapors from it can erase years or decades of age from someone, so most people who get close wind up vanishing into EmptyPilesOfClothing (which, incidentally, is the TropeNamer for that). The discovery of that lake was actually what enabled the development of the previously mentioned rejuvenating fluid, after people figured out how to harness its effects.
* ''DreamTales'' has a whole section of Age Regression comics that feature characters getting younger or older.
* Morgan of ''GenderSwapped'' after pestering Sven long enough to bend the rules for the two of them
* In ''Webcomic/ElGoonishShive'', [[MadScientist Dr. Germahn]] invented [[http://egscomics.com/egsnp/?date=2004-09-02 one.]]
* Ponce de Leon and his companion look for one in ''Webcomic/{{Oglaf}}'', but only come across the fountains of [[http://www.oglaf.com/fountain-of-doubt/ Doubt]], [[strike: [[http://www.oglaf.com/fountain-of-death/ Death]]]] [[http://www.oglaf.com/fountain-of-death/ Water So Good Even Dead People Want It]], and [[http://www.oglaf.com/fountain-of-girl/1/ Girl (NSFW)]].
* In ''Webcomic/KevinAndKell'', the vulture family have a time machine where they sometimes travel to the past. But in some cases, if used right, it can affect someone's age.
** Dolly who is a clone of Corrie, begins to age faster than usual. A new identity is created for her and she gets a job as a cleaning lady for the vultures. While cleaning she accidentally activates the time machine and is turned into a baby where she remains still.
** In other strips the characters are briefy turned into babies for laughs, but these are probably not canon.
* The Kids arc of ''Webcomic/{{Roommates}}'' where the resident [[TheTrickster magical troublemaker]] {{Schmuck Bait}}s ("What does this [[CrystalBall glowing orb]] do?!") the other main cast members into this and we learn that some people changed [[FormerTeenRebel a lot]]... others [[StaticCharacter not so much]]. Thank god the magic only lasted thirteen hours.
* In ''Webcomic/DocRat'', [[http://www.docrat.com.au/default.asp?thisItem=1137 heavy duty anti-ageing cream regresses a bird back to an egg.]]
* ''Webcomic/{{Karin-dou 4koma}}'': Seren and Elza's independent attempts at weight-loss magic actually turn them into children. Seren eventually turns herself back, but Elza prefers her new form.
* In ''Webcomic/{{Jix}}'' one of Lamerix's inventions instantly changes one's age, she loses it in the couch cushions and Lauren is accidentally turned into a child after sitting on it, though she eventually reverses it. Later on, she uses it to turn [[spoiler: Aragara, who had been artificially aged by growth hormones]] back into a kit.
[[/folder]]

[[folder: Web Original]]
* ''WhateleyUniverse'' example: retired U.S. Navy officer Sam Everheart was injured trying to save a HotScientist from bad guys. The 'hive' of nanites infected him and saved him.. by turning him into someone a lot younger. He now looks like his deceased 17-year-old daughter.
* Wiki/{{SCP|Foundation}}-[[http://scp-wiki.wikidot.com/scp-006 006]].
* In the aptly-named "Baby Boom" episode of ''WebAnimation/GothamGirls'', Harley is accidentally regressed into a baby.
[[/folder]]

[[folder: Western Animation]]
* In the Disney Channel cartoon series ''WesternAnimation/{{Jake and the Neverland Pirates}}'' episode "Pirate Sitting Pirates", Captain Hook as usual is being chased by Tic Toc Croc. As a result they both take a tumble knocking themselves as well as Jake and his friends into the pirate pool of youth, which can turn pirates into wee pirates. As a result they are all turned into babies. Now Smee and the other pirates must look for a flower that can turn them back.
* ''WesternAnimation/SuperSunday'': The entire series "Bigfoot and the Muscle Machines" was built around a young journalist, the members of a traveling monster truck show and a ruthless elderly billionaire named Adrian Ravenscroft searching for the Fountain of Youth. When Ravenscroft gets to it first, he turns into a young, 30-something man, vowing to destroy his adversaries. But the good guys destroy the fountain of youth, and it isn't long before Ravenscroft reverts to his elderly self ... fleeing but unknowing running into a swamp infested with hungry alligators.
* ''WesternAnimation/TheEmperorsNewSchool'' features the actual Fountain of Youth in one episode. Yzma uses it to become a (surprisingly attractive) teenager in order to trick Kuzco. It also features Pacha and Chica becoming teenagers, and ends with Yzma and Kronk becoming (somewhat freaky looking) babies.
* One episode of ''WesternAnimation/LiloAndStitchTheSeries'' involved an experiment known as the "Babyfier" that turned its victims into infants.
* ''SpiderManTheAnimatedSeries'': The [[EvilOldFolks aged crime lord]] Silvermane's long-standing goal was to find a way to restore his youth. Unfortunately, the AppliedPhlebotinum worked a little too well, and he reverted to infancy. A later attempt to fix it ''also'' works too well, restoring him to his original old age instead of to his target age.
** Adrian Toomes, the Vulture, shares the same goal and even uses the same AppliedPhlebotinum as Silvermane. It works out considerably better for him, to the point that he is the ''only'' villain in the entire series who gets everything he wanted in the end. He's also the reason Silvermane's attempt to undo his infancy works too well.
* In the WoodyWoodpecker short ''Born To Peck'', [[spoiler: this is added in at the last second by the animator to save the life of an elderly, suicidal Woody.]]
* One ''WesternAnimation/StarTrekTheAnimatedSeries'' episode had the Enterprise get sucked into a parallel universe where entropy was reversed and things aged backwards; they quickly started getting younger and younger, leading to an adorable 7-year-old Spock trying to hold the mission together.
* Two episodes of the original ''[[WesternAnimation/TeenageMutantNinjaTurtles1987 Teenage Mutant Ninja Turtles]]'' dealt with this; in "Back To The Egg" it happened to Leonardo and Michaelangelo, and in "Adventures In Turtle Sitting" Leonardo, Raphael, and Donatello turned into children and the slacker of the group Michaelangelo had to look after them.
** Another episode "Leatherhead Terror of the Swamp" when the mixture of the leftover mutagen that affected the Punk Frogs and Leatherhead is concentrated creating the Fountain of Youth. Shredder accidentally fell in the fountain turning him into a baby.
* ''CodeNameKidsNextDoor'' had an episode where the Fountain was revealed to be under the school, kept secret by one "girl" who had been using it for years. The Delightful Children from Down the Lane were naturally opposed to its existence and wanted to destroy it.
* Peach got turned into a baby in ''Series/TheSuperMarioBrosSuperShow'' after falling in the Fountain of Youth. To get her back to her real age, the brothers had to [[ReversePolarity make the waterfall in the fountain go up instead of down]] [[InsaneTrollLogic and put her in the fountain]].
** [[HilariousInHindsight That technically makes this episode the first appearance of]] [[VideoGame/MarioAndLuigiPartnersInTime Baby Peach]].
** One episode of the ''Adventures of Super Mario Bros. 3'' spinoff had one where Kooky's builds a time machine to take him and Koopa back in time so they can prevent Mario and Luigi from arriving at the Mushroom Kingdom, with the Marios and Toad following them back to stop them. Unfortunately, it malfunctions thanks to Koopa's impatience, so not only do they all go back in time, but they all get turned into babies too. [[HilariousInHindsight Which means this had our first appearances of Baby Mario and Luigi as well.]] Although this Baby Mario and Luigi ''still have their mustaches''.
* In the ''WesternAnimation/DuckTales'' episode "Sweet Duck of Youth," Scrooge looks for the literal Fountain of Youth so that he can live longer. It turned out that the fountain only made a person ''look'' younger when reflected in its waters.
* DonaldDuck tries to trick his nephews into believing they've found the fountain in "Don's Fountain of Youth." HilarityEnsues.
* ''WesternAnimation/QuackPack'' has the episode "Can't Take a Yolk" where Donald really ''is'' regressed to youth-- represented here by an ArtShift to his original character design from the 1934 short "The Wise Little Hen".
* In the ''WesternAnimation/JusticeLeague Unlimited'' episode "Kid Stuff", Morgan Le Fay's son Mordred gets his hands on a powerful amulet and, in a fit of pique after his mother insists he's too young to be responsible for it, banishes all the adults in the world to a pocket dimension. Morgan gets around this by turning some of the Justice Leaguers (Batman, Superman, Wonder Woman, and Green Lantern) into 8-year-old children so they can get the amulet back. Eventually, Mordred is tricked into breaking the spell that keeps him a child, and he vanishes into the pocket dimension as per the rules of his earlier spell. [[spoiler: In the end, it turns out that breaking the spell meant he still had eternal life but without eternal youth, and was now thousands of years old and effectively immobile, basically a vegetable that his still-young mother will care for -- ''Forever.'' [[FateWorseThanDeath harsh]].]] Of course, one wonders if Morgan can't just cast it again... or just won't.
* ''WesternAnimation/{{Ben 10}}'' also features the literal Fountain of Youth (though it's more of a natural pool or spring). Max turns into a 10 year old and is revealed to be similar to Ben at that age. Ben and the aliens turn into toddlers. It wears off.
** ''WesternAnimation/Ben10Omniverse'' has a de-aging ray used against Ben and Rook. Creator/TaraStrong returns to voice young Ben, and li'l Rook is ridiculously adorable... with a tail, which his species is born with but sheds at puberty.
* In ''WesternAnimation/SpongebobSquarepants'', Plankton develops both a super-aging ray and a de-aging ray. The latter ends up working a bit too well, [[RuleOfFunny turning him into an even smaller protozoa]].
* ''WesternAnimation/{{Futurama}}'' did this in "Teenage Mutant Leela's Hurdles", where overexposure to rejuvenating tar resulted in Professor Farnsworth going back to late middle age, and the rest of the Planet Express crew (including the robot Bender) becoming teenagers. An attempt to reverse the process made things worse, which instead just sped up the regressing, and everyone but Leela (who opted out of the cure, in order to relive the childhood she never had) started regressing into early childhood, most of the characters went so far back that they turned into fetuses ([[RuleOfFunny blueprints in Bender's case]]).
** And then the trope is parodied when they seek to be cured at the ''Fountain Of Aging''.
* Happens a few times in WesternAnimation/TheSuperheroSquadShow all due to messing around with time manipulation;
** The first time Thanos uses the Time Stone to de-age all of the occupants of a Skrull Ship and captain Marvel into babies, for his own amusement.
** Happens again when Iron Man's time machine backfires and turns Iron Man, Scarlet Witch and Falcon into toddlers, where Wolverine (to his dismay) has to babysit them, while the childish Hulk enjoys it. The [[RapidAging opposite]] happens to Ms. Marvel and Thor when Dr. Doom gets control over time, but Herbie then reverses all of the inappropriately aged squaddies back and in the process turns Dr. Doom into a toddler as well.
* An old episode of ''TheCareBears'' has this. One of the villains ends up turned into an infant and her partner has to watch after her.
* In an episode of ''HerculesTheAnimatedSeries'', Pain and Panic try to kill Hercules (again), this time by using water from a spring that reverses aging. They accidentally get water on not only Hercules, but on Icarus, Adonis, Pegasus, and Pain himself. Panic and Cassandra have to watch them since they're all infants until they can find a cure.
* In the ''BumpInTheNight'' episode "Baby Jail," Bumpy accidentally swallows some baby formula while trying to feed a baby and becomes one of them.
* Occurs in a great many cartoons in general. Often, with the humorous side-effect of the subjects eventually reverting to their true age while wearing a diaper.
* ''WesternAnimation/TheKarateKidTheAnimatedSeries'': In "Over the Rainbow" Miyagi, Daniel, and Taki stumble on a hidden community with one fueled by the shrine.
* Two instances happened in ''WesternAnimation/KimPossible''. The first was when in the MadeForTVMovie "A Sitch In Time" where the [[VillainTeamUp teamed up bad guys]], having possession of time traveling idol, used a device to make themselves toddlers so they could infiltrate the titular hero's youth.
** The second was in an episode where Ron was continuously sent through a machine that turned adults into babies. He went through so many times that when he finally got back to his own age, he was wearing a diaper.
* There have been a few episodes in ''WesternAnimation/DarkwingDuck'' that feature this.
** An elderly villain attempted to actually make one of these so as to regain his youth and become immortal. His plan worked and he was restored to his prime. Unfortunately, in a fight with Darkwing Duck and Herb, they all became babies. In the end the fountain was destroyed and his henchmen were turned into babies as well while Darkwing and Herb turned back.
** In "Disguised the Limit", Darkwing is framed for a crime he did not commit. So a scientist blasts him with a ray gun that will turn him into anything he sees. At one point he turns into his daughter and a baby.
** In one episode, Darkwing becomes super fast but the more he does it, the older he becomes (see overnight age up). In the end he fixes it by running backwards to become younger...at one point a little too much and becomes a kid.
* In ''WesternAnimation/TeenTitans'' Warp is reduced to infancy after his time suit malfunctions.
* In one ''BettyBoop'' cartoon, the patent medicine she and her pals are peddling turns an old bearded man into a large baby - and the baby accompanying him into a tiny old bearded man.
* In one episode of the third season of ''WesternAnimation/WinxClub'', the Winx had to retrieve water from a magical stream that was capable of turning back time so they could save Faragonda who had been transformed into a tree by Valtor. However, they had to be careful not to touch the water, realizing that doing so could cause them to turn back into children. Near the end of the episode, after Flora earns her Enchantix after saving her younger sister from the Trix, she then throws the Trix into the water, turning them into preteens. Of course, the Trix are back to normal in later episodes, so Valtor must've been able to restore their true ages.
* In ''Disney/{{Tangled}}'', originally it was the magic flower that Mother Gothel used to keep her young. But after the Queen drank the flower and gave birth to Rapunzel, Gothel got her Fountain Of Youth from Rapunzel's hair.
* The "Little Muriel" episode of ''WesternAnimation/CourageTheCowardlyDog'' has Muriel being turned into a mischievous little girl by a freak tornado. It then turns out the only way to undo the effect is to throw her into a tornado spinning in the opposite direction of the original one - which entails flying to the southern hemisphere.
* Leave it to ''WesternAnimation/{{Superjail}}'' to come up with a twisted, disturbing take on this one. When the Warden is feeling old and decrepit on his birthday, Jared buys him some "ancient Chinese mystery butter" that's supposed to restore someone's youth. It ends up getting put on the birthday cake, though, leading to a bunch of inmates regressing to toddlers. Toddlers who then proceed to violently kill each other.
* Happens to Batman [[note]] again[[/note]] in ''WesternAnimation/BatmanTheBraveAndTheBold'' after he was zapped by [[{{Shazam}} Dr. Sivana]] starting as a teenager, then a toddler, and then a baby.
* ''TheProblemSolverz'' episode "Time Twister" features a roller coaster capable of traveling through time, which Alfe takes advantage of by going back in time to eat pizza over and over again, and he becomes younger as a result.
* In ''WesternAnimation/TheMask'' episode "Little Big Mask" Stanley Ipkiss creates a cream that causes him to get younger by the hour and he as The Mask must find a way to fix it while Peggy tries to keep him focused.
* In the cartoon version of SpaceAce, the Infanto Ray made some appearnces; one of them was episode 3, in which the victim was Borf. Another example is episode 6, where the Infanto Ray was just a round circle. However, it made its return in episode 11, in which Borf uses it on the vicims, and one of them was Kimberly, but after Dexter was brainwashed with the brainwashing device, Kimberly turned back into her adult form right after Dexter grabbed Kimberly while in the prison.
** Another ray, the ''Age Ray'' appeared in another episode before episode 11. The Age Ray was meant to be used on Dexter so that Dexter can remain as Ace, but when Borf gets hit by the Age Ray, he does not turn into a baby, but rather into a teenager, and Borf energizes at random times throughout the entire episode like Dexter.
* In an episode of "Adventures of Sonic the Hedgehog", Dr. Robotnik plans on defeating Sonic by making him so old, he won't be as fast. As usual Scratch and Grounder mess things up by putting the device into reverse, turning Sonic into a toddler and Tails into a baby. Later Robotnik is too turned into a toddler. At the end Robotnik is turned into an old man.
* ''RockosModernLife'': Rocko, Heifer, and Heifer's Grandfather are on a cruise filled with senior citizens when they cross The Bermuda Triangle, which alters their ages. Giving us a mix of overnight age up and Fountain of Youth, all the elderly revert back to young(er) adulthood, the ship's crew become babies, and Rocko and Heifer become elderly.
* A while ago, McDonalds released cartoons on VHS featuring Ronald [=McDonald=] and his friends having adventures. One such cartoon saw them go to an amusement park called Birthday world where him and his friends are turned into toddlers and babies.
* In an episode of the cartoon ''WesternAnimation/YogisTreasureHunt'' called "Secret Agent Bear", Yogi and his pals spoof James Bond movies. In it they accidently fall into the fountain of youth and the adults become little kids and the kids become babies. Later the villian uses the water to turn world leaders into kids and then is turned one himself at the end.
* The final ''TheFoxAndTheCrow'' cartoon, "Punchy De Leon" has Fox and Crow as con men who claim to have found the Fountain, hoping to get rewarded by the King of Spain. When the King wants them to bring it for real, they set off to Florida to find it.
* In the ''TinyToonAdventures'' episode "Love Disconnection" (and within ''that'', the [[TwoShorts segment]] called "The Amazing Three"), [[ValleyGirl Shirley the Loon]] tries to make the moves on an older male duck at a senior dance by asking him what his [[WesternZodiac astrological sign]] is. Out of his beak comes AntiquatedLinguistics as he belittles her, telling her how childish and unfounded astrology is. However, she has such a hard time understanding him that ''[[HilarityEnsues she reverts into a baby]]''! Prior to that, Shirley said that she would impress the duck with [[{{Irony}} her "keen wit and intellect"]].
--> '''Shirley:''' Like, umm, what's your sign?
--> '''Duck:''' Ah! A devotee of the unseen world. The universe fantastique. Almost amusing in an infantile sort of way, though terribly childish and laughably unfounded. (Shirley reverts into a baby)
--> '''Duck:''' I believe [[{{Creator/Voltaire}} Voltaire]] put it best when he likened astrology to astronomy as the mad daughter of a wise mother. Don't you agree?
--> '''Shirley:''' I go like, [[BabyTalk nappy-poo now. Goo googoo gaa gaa gaa]]? (she crawls away)
--> '''Duck:''' Quite.
** The episode "Fields of Honey" reveal that laughter keeps toons young. This is shown where upon having people laugh at her cartoons after so many years, an elderly Honey is restored to her prime.
* ''WesternAnimation/MyLittlePonyFriendshipIsMagic'': Age spells can only be performed by the highest-level unicorns. Trixie is able to turn Snips into a baby and Snails into an old stallion with her magic boosted by an Alicorn Amulet; Twilight Sparkle, on the other hand, is unable to reverse it. In order to rid Trixie of the corrupting amulet, Twilight fakes it by claiming to have an equally powerful artifact while having Apple Bloom and Sweetie Belle impersonate Applejack and Rarity respectively. Twilight pulled it off for real in "The Cutie Mark Chronicles", though, though not intentionally; during her entrance exam to magic school, she was startled and lost control of her magic, turning the not-yet-hatched Spike into an adult dragon.
* The second to last episode of ''WesternAnimation/{{Rugrats}}'' (AKA Fountain of Youth) has Tommy, Chuckie, & Kimi think that the fountain of youth exists. They are happy until Angelica tells them that she will be in charge when its powers take effect on the adults & tricks them into thinking that the fountain in the lake has said powers. After several unsuccesful attempts at preventing the adults from going into the lake, they decide to drain the lake...[[spoiler: by pulling on a chain which might actually be attached to a boat which is far too heavy for them to move by even an inch.]]
* In a cutaway gag on ''WesternAnimation/FamilyGuy'', Ponce de Leon Griffin finds the Fountain of Youth and takes a dip, keeping his head above water. When he emerges, his body is the size of an infant, but his head is still adult-sized; he promptly topples over.
* ''WesternAnimation/JackieChanAdventures'':
** The Dog Talisman gives its holder immortality. While it doesn't make the holder look younger, it makes him ''feel'' younger. Thus Uncle becomes incredibly strong and agile like he used to be.
** Characters sometimes get turned into children by spells.
* An episode of ''WesternAnimation/TheJetsons'' "Boy George" has George turn into a kid, though his voice is exactly the same. Another episode averts it by having Elroy turn into an old man.
* ''WesternAnimation/TransformersRescueBots'': Dr. Morocco stole a mechanical FountainOfYouth that he uses to stay young but he must use it very often due to the effects of the machine which make him age much faster than usual.
* ''WesternAnimation/JohnnyBravo'': In one episode, Johnny drinks a potion that reverts him to infancy- physically, at least- to the delight of his mother... until she gets busy and sends him off to day care with an attractive caretaker, to his delight. In the end, he's restored to his adult body.
* In ''WesternAnimation/AdventureTime'', the ([[ReallySevenHundredYearsOld apparently]]) 18-year-old Princess Bubblegum suffers an accident in which she loses some of her body mass. Being [[ExactlyWhatItSaysOnTheTin a sentient wad of bubblegum in a generally princess-like shape]], she is saved by being reconstructed in the shape of an apparently 13-year-old princess. Since TheMindIsThePlaythingOfTheBody, this also causes her personality to take on the traits of a 13-year-old. The situation is, [[StatusQuoIsGod of course]], temporary.
* The ''WesternAnimation/OggyAndTheCockroaches'' episode "Back to the Past" features Oggy, Jack, and Bob accidentally facing the wrath of a witch and turned into elementary school-aged kids, with Olivia and Joey forced to track the witch down to reverse the spell, while Dee Dee and Marky watch over the three. [[spoiler: In the end, the same ends up happening to Joey, Dee Dee, and Marky.]]
* In a relatively rare example of kids getting younger, the ''WesternAnimation/PhineasAndFerb'' episode Agent Doof has the titular characters being turned into babies. Needless to say, Candace ended up a BadlyBatteredBabysitter in record time. And at the end of the episode, even their mother and the Fireside Girls are turned into babies. Candace is obviously exasperated, and [[BreakingTheFourthWall openly hopes it wears off by the next episode]] ([[StatusQuoIsGod which it also obviously does]]).
* In ''WesternAnimation/YellowSubmarine'', The Beatles and Old Fred regress to childhood and young adulthood respectively after travelling backwards through the Sea of Time. When they end up reversing the change, they end up [[RapidAging reversing it a bit too much]].
[[/folder]]

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