History Main / WaterTriggeredChange

The commonality of water makes this a useful plot device to the author. The effected character can have indirect control over their form most of the time, but the plot can just as easily take that control away.

* The titular character of ''Literature/EmilyWindsnap'' transforms into a mermaid whenever she's submerged in water.

* ''Manga/CrayonShinChan'' has a FracturedFairyTale episode based on ''Literature/TheLittleMermaid'', where the titular character and his andromorphic pig sidekick Buriburizaemon need to help a merman ''prince'' (GenderFlipped version of the original mermaid) win over the heart of a princess. Their first step is helping the prince gain legs through a MagicPotion, but the witch who made the potion for them warns of its side effects that the prince will revert to a merman if exposed to water. As luck would have it, the prince gets caught in an unexpected rain that reverts him back to a merman, [[ARottenTimeToRevert right in front of the princess]].

* In ''Animation/BoBoiBoyTheMovie'', Bora Ra gives Adu Du and Probe a task; to feed the alien squid Kurita, and not let it get wet. Probe questions how they'd get it wet - but is interrupted when they are ejected from the spaceship and into the ocean. Kurita turns into a GiantSquid as a result.
* In ''WesternAnimation/{{Luca}}'', the sea monsters can take human form, but will turn back into their true form when they are exposed to water. Even if it's just a portion of their body that gets wet, that portion will revert.

* In ''Film/{{Aquamarine}}'', the titular mermaid is able to change her fish tail into legs during the day, but she'll turn back if her legs get wet.
* Madison in ''Film/{{Splash}}'' turns back into a mermaid whenever her legs get wet (drying them turns them back into legs), as demonstrated in the scene where the MadScientist Walter sprays her with a hose.

* In ''VideoGame/PrinceOfPersiaTheTwoThrones'', the Prince acquires a "Dark Self" that takes over his body during times of extreme danger (though the player is still in control of the Prince), and can only change back if he touches water.

* In ''Animation/BoBoiBoy The Movie'', Bora Ra gives Adu Du and Probe a task; to feed the alien squid Kurita, and not let it get wet. Probe questions how they'd get it wet - but is interrupted when they are ejected from the spaceship and into the ocean. Kurita turns into a GiantSquid as a result.

* ''WebOriginal/LoomingGaia'': Mermaids, who are human girls cursed by undines, take on their aquatic form when their hair gets wet.

* ''Toys/{{Transformers}}'': The European-exclusive late-G1 Aquaspeeders and their {{Evil Counterpart}}s Stormtroopers are teams of cars with water squirting weapons. Their unique gimmick was that the water would change the color of some of their plastic. While technically it's the temperature which causes the color switch, they're advertised as water being the catalyst for the change.

A {{Shapeshifter}} character whose specific {{Transformation Cause|s}} is getting their body drenched with water. This tends to be a property of [[OurMermaidsAreDifferent Mermaids]], who will often take a human form when outside of the water and revert to their mermaid form upon either reentering a body of water or simply getting wet.

The transformation can be VoluntaryShapeshifting or InvoluntaryShapeshifting depending on the character coming into contact with water willingly or not. The shapeshifter might be BlessedWithSuck depending on how annoying this is to them.

* ComicBook/{{Aquaman}}: After Aquaman's first battle against Dead Water, he discovers the monster is actually Jonah Kendry Payne, a normal man mutated against his will. The hero believes the transformation is triggered whenever Jonah comes into contact with water, resulting in the man being confined in a special dry chamber until the researchers can find a cure for his condition. Unfortunately, Dead Water resurfaces after Jonah is exposed to his own tears, and escapes to wreak havoc again. [[spoiler:Subverted when a later arc establishes that Aquaman's theory was incorrect; the real trigger for the transformation turns out to be the feeling of extreme distress]].

* ''Literature/TheLaundrySeries'': Ramona Random, a [[OppressiveStatesOfAmerica Black Chamber]] operative Bob works with in ''The Jennifer Morgue'', is a [[HalfHumanHybrid half-mermaid]] (merfolk in this series being FishPeople who were created by the [[Franchise/CthulhuMythos Deep Ones]] to be intermediaries with humans). After taking an extended dive deep in the ocean during the climax of the book, her body starts to undergo a metamorphosis to take on more merfolk traits; when she next appears in ''The Annihilation Score'', she now has trouble walking on land and needs to spend much more time out of the day in the water than previously.

* In Susan Dexter's ''The True Knight'', Savrin, pushed into the river, turns into an otter until a wizard catches her and pulls her out, whereupon she turns back. Later, he pushes her in again to save her, and she turns to an otter again, and nearly drowns in her clothes. When Titch rescues her, she turns to a duck and then a salmon, trying to escape, but remembers nothing after.

See also ElementalShapeshifter for someone who can transform ''into'' water and MakingASplash for someone who can ''control'' water. Compare InstantOracleJustAddWater when water triggers visions.

* ''Literature/CaptainUnderpants'': Mr. Krupp, who has been hypnotized to think he is the titular underwear-clad superhero, snaps out of the hypnosis and reverts to his normal personality when he touches water. His Purple Potty dimension counterpart, [[EvilTwin Captain Blunderpants]], works the opposite way; he transforms into him from the kindly alternate Mr Krupp when he gets splashed with water.

* ''Literature/CaptainUnderpants'': Mr. Krupp, who has been hypnotized to think he is Captain Underpants, snaps out of the hypnosis and reverts to his normal personality when he touches water.

[[folder:Toys]]
* Many premium ''Toys/HotWheels'' cars are advertised as changing color in water, even including playsets designed to pour water on them to facilitate this gimmick. Like many other toys with a similar gimmick, it's the water's temperature which causes the color switch, but as far as the packaging and advertising is concerned, it's water which causes them to change color.
* ''Toys/MermaidHigh'': The Merfriends grow their tails whenever they're in the water or get wet (even just a little wet), and their legs appear when they're dry.
* ''Toys/{{Transformers}}'': The European-exclusive late-G1 Aquaspeeders and their {{Evil Counterpart}}s Stormtroopers are teams of cars with water squirting weapons. Their unique gimmick was that the water would change the color of some of their plastic. While technically it's the temperature which causes the color switch, they're advertised as water being the catalyst for the change.

[[folder:Video Games]]
* ''VideoGame/RuneFactory3'': Pia is a mermaid who can take on a human form when dry, but her legs turn into a mermaid's tail when she gets wet. In the game, she takes on her mermaid form when it's raining outside ([[GameplayAndStorySegregation Oddly enough, she still can move on dry land at her normal speed as a mermaid despite claiming her tail makes it difficult to move around]]).
* ''VideoGame/WarioLand'': Getting hit by certain enemies' attacks can result in Wario becoming a zombie, a vampire, overweight or drunk. Touching a droplet or a body of water will cancel the transformation and revert him back to normal.

[[folder:Web Animation]]
* In Episode 21 of ''WebAnimation/{{Japanoschlampen}}'' by Creator/{{Coldmirror}}, Ass, in an obvious parody of ''Manga/RanmaOneHalf'', accidentally falls into a spring and is cursed to turn into a girl when wet. Ass doesn't seem to care about it that much and [[VulgarHumor changes from his signature dick jokes to tit jokes.]]

[[folder:Webcomics]]
* ''WebComic/ElGoonishShive'': Referenced twice in regards to Elliot's GenderBender ability (more specifically, referencing ''Manga/RanmaOneHalf''). Sensei Greg [[https://www.egscomics.com/comic/2005-02-28 dumps a bucket of water]] on Elliot's head to test it, only for Elliot to shout that that's not how it works. Later on, when [[spoiler:Ashley]] accidentally sees him transform, she asks him [[https://www.egscomics.com/comic/2013-12-27 if he needs hot water]] to turn back.
* In ''Webcomic/SkinDeep'', Nixie saliva causes people to grow gills while wet.

[[folder:Web Original]]
* ''WebOriginal/LoomingGaia'': Mermaids, who are human girls cursed by undines, take on their aquatic form when their hair gets wet.
[[/folder]]

[[folder:Western Animation]]
* One of the villains in ''WesternAnimation/JamesBondJr'' had implants allowing him to transform his face. However, due to NoWaterProofingInTheFuture, whenever he got wet, we got a mild case of FacialHorror.
* ''WesternAnimation/ThePrinceOfAtlantis'': In the first episode, after Jaurice dies in a submarine incident, Agata uses his magic to bring him back to life and in the process attempts to turn him into an Atlantean, like him. Instead, Jaurice becomes a hybrid who will transform into an Atlantean any time he comes in contact with water, but returns to fully human if he dries up, enabling him to live both on land and under water.
* ''WesternAnimation/WorldOfQuest'': Dousing the Katastrophe Brothers in water causes the three of them to merge together into a stronger hybrid form, which can be undone by pulling out the cork in the back of their head. However, they are capable of bypassing this weakness by being somewhere where it's raining, which allows them to instantly merge again seconds after being separated.
* ''WesternAnimation/XiaolinShowdown'': Dyris the mermaid looks like what most mermaids look like when she is in water. On dry land though, she changes into her true form which is an EldritchAbomination. Keeping her soaked in water will render her harmless, though. Klofang even states that fighting her out of water is a bad idea.
[[/folder]]