Hair Colors are an easy way to distinguish one person from another at a glance. At times, it might drive a person to dye or even bleach their own hair to change its color (blonde is a common goal, due to the stereotypes of it being more glamorous). But some people aren't satisified with just one hair color. Oh no. Their hair has to keep changing color frequently. The new shade can be common, implausible, or even outright impossible. The changes must happen a number of times, and they may be justified by use of hair dye, or any sort of Applied Phlebotinum — up to and including actual magic (though it's not necessarily a case of Magic Hair). It doesn't even have to happen to real hair, so characters who constantly swap wig colors come under this trope.
The color changes may pass without comment from others in the work, or drive someone up a wall trying to figure things out. Sometimes, even the subject of the changes might not appear to notice or care; in other cases, they might be pleased. The changes can be accompanied by a makeover, but this is less likely if they take place regularly or are a result of mood swings. Hilarity can ensue if the character hates what happens to their hair while being powerless to stop it.
This trope can occur in any medium, but some are more common than others (e.g. video game examples are near non-existant). Naturally, this includes Real Life, though due to the effects of repeated dyeingnote that is, hair becoming rough, bleached, falling out, losing oils, breaking, and generally becoming a pain to care for and style,most people don’t do it. Due to happening many times on a single person, it isn’t a type of Expository Hairstyle Change. Usually.
Compare Kaleidoscope Eyes for the same thing in a different place, and Multicolored Hair, which is strictly about hair that is simultaneously of multiple colors/shades. Of course, the two tropes may overlap sometimes. Compare and contrast Expressive Hair, when the hair changes style. Supertrope to Power Dyes Your Hair, where the color change only occurs due to a transformative power-up.
One of the Common Mary Sue Traits, along with being a way to give someone a Distinctive Appearance. See also Locked into Strangeness, for permanent hair colour changes. May be a result of someone just wanting to be special or Anime Hair (where it can overlap with You Gotta Have Blue Hair). Voluntary Shapeshifters often have this, as can somedepictionsofteenagers.
When Light and L confront each other in Death Note, or meet each other on the street, Light shines a deep, blood-like red, and L an almost naval blue. Sometimes this appears as a tiny aura around their bodies, other times their hair and eyes glow that color. Their hair color can also indicate mood.
Urusei Yatsura: In the manga, Lum had full-blown rainbow-colored hair that shifted colors. As the manga progressed, Rumiko Takahashi changed Lum's hair color to green to match the anime, since it was changed there for ease of drawing.
In color chapters of the Dragon Ball manga, Karin's fur is never the same color twice. This is never commented upon. (For what it's worth, he was based on a black cat...)
Delirium from The Sandman; her hair color changes depending on her mood. It's also multicolored at any given time.
Ramona Flowers dyes her hair every two weeks, which Scott Pilgrim freaks out over. In Scott Pilgrim Vs The World, Knives tries to dye her hair blue in order to compete with currently-blue-haired Ramona.
Violet from Ultra Violet, partially because of how the film is designed to resemble a comic book.
Diamonds Are Forever - when Bond first meets Tiffany at her apartment, he's perplexed to see her change from a blonde to a brunette to a redhead in quick order.
Talia of The 6th Day has a different hair color (usually something bright). She gripes about having to redye it every time she gets a new body.
Natalia Tena's portrayal of Tonks (see below) doesn't change her hair quite as much as her book counterpart but is still shown with purple, red, white, brown and blonde hair across four Harry Potter films.
Ten Inch Hero has Priestly, whose mohawk changes color changes in every scene. At one point, it's even two different colors.
Tonks often changes her hair color; it is usually a shade of bubblegum, but can turn ginger when she’s angry, gray for a disguise, or any number of other colors at her every whim. Justified as she is a metamorphmagus.
Her son is also a metamorphmagus. Lupin mentions that Teddy had black hair when he was born, and it turned ginger by the time he'd left. Later in the book, he shows someone a picture of Teddy with turquoise hair.
Shifting hair colors is a genetic trait shared by members of Idris' royal family in Warbreaker. Hair changes color depending on the person's mood; it turns white when they are scared or nervous, black when they are calm or feeling confident, red when they are angry, and blonde when they are happy. As shown by Siri's character development, it takes a lot of maturity and restraint to keep one's hair the same color for a long period of time.
Acheron Parthenopaeus from The Dark Hunters series can change his hair color at will. So far it's been black, brown, green, purple, platinum silver, and black with red streaks, among others. Justified, since he is an Atlantean god.
Danestar Gems in the Federation of the Hub stories always has the same hair colour as her clothes; she uses wigs, which (since she's employed by a detective agency) are usually packed with surveillance gadgets.
One possible power in Xanth is changing your hair color.
My Sweet Audrina by V. C. Andrews notes that the women of the Adare (except Vera, a redhead) are born with what they call "chameleon hair", which appears to change colours according to the light.
Newter of Worm is an orange lizard with Animal Eyes and oft-changing dyed hair.
In Children of the Red King, Olivia frequently dies her hair blue, green, purple, etc. In fact, it's a shock when the characters see her with normal brown hair.
Mrs Slocumbe, from Are You Being Served?, has hair that switches colors frequently. Originally, actress Mollie Sugden dyed her hair different colors, but when it damaged her hair she began to wear varying wigs instead.
Christine Nelson (from Degrassi) dyes her black hair bleach blonde in season 8. In season 9 she inexplicably now has red and blonde hair. (To be fair, the character IS a hairdresser. It's likely that she frequently experiments with hair styles.)
Enforced in The Many Loves Of Dobie Gillis. Dobie's actor (Dwayne Hickman) was made to dye his hair blonde in order to distance him from a previous role. When the show was well established, he was allowed to return to his natural brown hair color; however, at times he had to go blonde again.
Oz dyes his hair so often it's difficult to tell what its natural color is.
Willow: Your hair! ...is brown. Oz: Oh, yeah. Sometimes.
Anya tends to have a new hair color and style for every episode she appears in.
You'd be hard pressed to name two episodes where Lillian of Boardwalk Empire has the same hair color and style.
Lucretia from Spartacus: Blood and Sand rotates between her natural hair color and various colored wigs. Later we find out she wears them to honor her old friend Gaia, whose wigs they originally were. Truth in Television as the hair fashions were constantly changing in Rome so most noble women used wigs and hair pieces to keep up with them.
Paige from Charmed whose hair is a different colour each season. Black in S4, Red in S5, Blonde in S6 and brown in the last two seasons. Phoebe also had six different hairstyles in the fourth season. In the premiere she was dark blonde but had gone all the way to an almost black hue by the finale.
Sonika of a Vocaloid is able to change her green hair color according to her Twitter messages.
Britney Spears has dyed her hair many colors over the years, though blonde has always been predominant.
Through the miracle of wigs, Kyary Pamyu Pamyu has a different hair color and length almost every time we see her.
Katy Perry is constantly changing her hair colors. At various times, it's been black, blond, red, blue, pink, purple and orange.
Anette of Nightwish frequently dyes her hair different colours. As of the end of July 2012, she was a redhead; come September, she's blond.
During the Hybrid Theory (an album) period, Mike Shinoda of Linkin Park was known for dying his hair red.
Matt Bellamy of Muse often dyed his hair various colors during the Origin Of Symmetry period, notably red, blue, and blond.
This is a common trope in the K-Pop industry, seen frequently on Daesung, T.O.P., and excessively, G-Dragon, all of Big Bang.
Lene wore no fewer than four colored wigs for Aqua's "Lollipop (Candyman)".
Gerard Way of My Chemical Romance has changed his hair a lot. He's had it black, bleached blond and cut short, then long and bright red for Danger Days.
Everyone (except Leo) in VIXX has hair that changes every once in a while, but Ravi is notable for changing his hair color four times in a six month period.
Girls' Generation: Sunny frequently changes her hair colors through dying her hair or wearing wigs. So far, her hair has been in 7 colors (and counting).
Some Create-a-Wrestler information websites for WWE games tend to list William Regal's hair color as either blonde, brown, or red. He seemingly has Kaleidoscope Hair based on the lighting, length, and dampness of his hair. If it's short and slicked back, and he's in a not so well-lit room, it can look brownish. If it's short and slicked back, but the lighting is better, like in a WWE arena, then it can look like a redhead. If it's long and dry, and he's in a well-lit room, then it can his natural blond mixed with a bit of gray.
Jeff Hardy has had numerous colors to his hair.
The Kat liked to have multi coloured hair every week around mid-2000. She alternated between blonde and black hair several times during her stint in WWE too.
Naomi on NXT season 3 had different colour highlights in her hair every week though she stopped it altogether by the end of the season.
Roxxi Laveaux in TNA when she was the Voodoo Queen. The repeated dying ended up stripping her hair, resulting in a head shave at the 2008 Sacrifice PPV.
Fóla Aensland of The Origin of the Keys can manipulate her hair and eye colors at will. This can be intended to appeal to certain peoples' tastes, but is mostly done just to amuse herself.
In some scenes of Final Fantasy XV, Noctis' hair looks like a shade of silvery blue. Of course, in other scenes his hair seems black or silver, and in the early stages it was meant to be brown.
In RosenkreuzStilette, Spititia has a version of this which overlaps with Power Dyes Your Hair: using different weapons from the other RKS members she'd fought will change her hair color corresponding to the hair color of the original user.
This happens to Nanase (whose hair turns black when her magic burns out) and Susan (when she goes through an angst-induced awakening) in El Goonish Shive.
Ping from MegaTokyo can change her appearance in response to user feedback. The most obvious changes are to her hair. So far, she's had pale grey, hot pink, and turquoise.
For a long time, Peejee from Something Positive would have constantly changing hair, until Randy got tired of changing it.
Minus: Minus's hair changes from strip to strip, ranging from red to blue and green without comment – then again, she is omnipotent. It adds to her surreality.
Flipside: Crest's wizard girlfriend who can change her hair's color and style based on her emotions.
Kyle, the author and main character of Imminent Moose frequently changes his hair color on a whim.
Zoophobia: Jestine's (already multi-colored) hair constantly changes with every scene.
In Shinkutokimekisempukaku (or just Shinku! for short), Leroy is drawn with a different hair color in every panel. In the first strip where this is evident, the author commentary explains that this is an exaggeration of the real Leroy's habit of frequently dyeing his hair. Similarly, Cary's hat shows a different icon on the front in every panel.
In "Subnormality" the pink-haired girl switches between neon pink and brown, once in the middle of a conversation with another character. Her explanation: 'I do this a lot'.
Ophelia of Earth 14 dyes her hair and has a different color in each appearance. Her natural hair color is dark brown, as seen in the portions that aren't dyed.
In the later Yu-Gi-Oh! The Abridged Series "Marik's Council of Doom" videos, Dartz's hair changes color between almost every cut (as a parody of the below mentioned Coiffio).
When Lupa released her commentary for Undefeatable, her first video review, she explained that she has been changing her hair color regularly for most of her life, and that her first few videos (including Undefeatable) caught her at a rare moment when she had returned to her natural color.
Her workmate MarzGurl also likes to change her a lot, but many times reverts to her natural brown.