Paint It Black
A specific form of Evil Costume Switch, one that requires no effort whatsoever on the part of the newly evil party.
See, your Transformation Trinket, your Empathic Weapon, and your costume aren't too happy with your Face Heel Turn. Being inanimate objects, though, the only way they can express their disapproval is to turn black and evil-looking—goodbye Frills of Justice, hello Spikes of Villainy. The transformation usually, if not always, happens right before your eyes and those of your astonished friends, just for dramatic flair.
A possible variant is when a character happens to be split between good or evil or gain an Enemy Without (sometimes just for a Mirror Match); the Evil Twin (or both) might immediately get Color Coded for Your Convenience in the process. In visual media, it naturally helps the viewer telling apart the good guy and the bad guy.
This trope is named for The Rolling Stones song "Paint It, Black", although they are completely unrelated.
Important Note: Please read the trope description before adding any new example. It is not about characters getting a new black (or even darker) outfit. It's about a costume/color change being spontaneous. Unfitting examples will be removed.
- Sara in Mermaid Melody Pichi Pichi Pitch flashes back to her Freak-Out that destroyed the Indian Ocean and killed Kaito's parents; she used to have bright red hair, but once she embraces her hatred and fear, her hair and pearl (and, in the manga, costume) turn black.
- Messenger Nia in Tengen Toppa Gurren Lagann gets this with Tron Lines.
- Sailor Moon
- Brainwashed Tuxedo Mask fights by throwing black roses. In some "I Know You're in There Somewhere" Fight scenes in the anime, the rose in his hand is flickering between red and black.
- The normally black-clad antagonist Sailor Tin Nyakano only gets partially purified by Sailor Moon, resulting in a half-black and half-white costume.
- The Devil Suit in Corrector Yui is an insta-corrupted Angel Suit.
- Inverted in Bleach—Ichigo's normal outfit is black and his Enemy Within is a completely white version of himself with black teeth and eyes. While Ichigo's Super Mode turns his sword black, "Hichigo"'s version turns it white. Justified in that white is the color most associated with death in Japan.
- ShineGreymon Ruin Mode (a berserk, corrupt power-up), in Digimon Savers, is a darker, duller palette swap of ShineGreymon Burst Mode (the true power-up), though, in this case, the dark version occurs first.
- Also, in Digimon Adventure 02, Ken forces Agumon to become Metal Greymon when under the control of a Mind Control Device, and when he does, he's gray instead of his usual orange (if you take the card game as canon, this means he's a Virus type instead of a Vaccine type now—think of it as Digimon's version of Elemental Rock-Paper-Scissors), though his Agumon form remains unchanged.
- In Majin Tantei Nougami Neuro, in the latest chapters, Sasazuka gets this along with his (partial) Face Heel Turn. Cue fangirl drooling.
- In Mai-Otome, Nina's Robe, school uniform and transformation silhouette all change to darker colors following her Face Heel Turn.
- Trisha Elric in Fullmetal Alchemist has brown hair, but in the 2003 anime version, when she is "resurrected" as a homunculus named Sloth, her hair is jet black. Black hair and paler skin seem to be a general effect on the homunculi of the anime. Lust's human form was Ishvalan, and they're all mostly middle-eastern in appearance.
- In Hellsing, after Seras finally drains a human to death and unlocks her full power as a vampire of Alucard's line, her yellow Hellsing uniform turns red. Or maybe that had to do with the scenes both before and after her transformation, where it liberally soaked in blood.
- In Eleven Eyes, when Lisette becomes Liselotte, her Elegant Gothic Lolita outfit changes from white to black.
- In Transformers: Kiss Players, when Starscream possesses Atari Hitotonari, her nurse outfit turns black.
- In "Fate/Zero", an unwilling Irisviel has this, when her mind gets absorbed by all the Evils in the World - Angra Mainyu
- Mary Marvel's white costume switched to black when she received Black Adam's powers in Countdown to Final Crisis—which had the side effect of turning her evil.
- Inverted for Raven of the Teen Titans, who usually switches from her dark-blue to a white outfit when her demon father Trigon's influence becomes too great.
- When Supergirl was exposed to black kryptonite in a ca. 2005 storyline, she was split into her normal self and an evil (and oversexed) alternate personality that wore a black-and-silver version of her normal costume.
- Jean Grey/Phoenix. When she first becomes Phoenix, the new suit is just there, and when she becomes Dark Phoenix, it turns red. Later in the original Phoenix arc, she can tell how close she is to losing control by what she sees her costume is doing. In the Endsong storyline, she frequently changes from green to red as her personality shifts between "Jean with Phoenix powers" and "cosmic destroyer". When her issues are finally resolved, it becomes white. (The white suit has its own meaning, which, like all things Phoenix, is needlessly complicated.) 
- Another Phoenix example is when Emma Frost briefly possesses the Phoenix Force during Endsong, her normally white costume becomes black and gold and more slutty. Yes, it's possible.
- Every Phoenix host seems to get a new Phoenix-ified version of their outfit. Even Spider-Man, though he wasn't actually a Phoenix host at the time, so where'd the outfit come from?
- Evil Sonic (a.k.a. Scourge) from Archie comics eventually goes green and vile-looking when he absorbs enough energy from the Master Emerald, which also helps drive him a bit mad and he becomes even more evil when Sonic points out their similarities. In the end, this leads to his using his super form, a bizarre inverse of his usual color scheme with purple hair, black eyes with red pupils and even a slight outfit change, with the red and green parts becoming purple and blue. It's a surprisingly creepy looking form, fitting for how crazy he's become.
- Inverted in Aladdin where Jafar's outfit turns white after he uses his first wish to become Sultan. Then again, he was already evil in the first place, and the white outfit seems like the traditional color for male Agrabah royalty.
- Dark Mercury in Pretty Guardian Sailor Moon, whose Dark Transformation Sequence was much cooler than her good one.
- Buffy the Vampire Slayer:
- As Willow powers up for her homicidal Freak-Out, the Phlebotinum involved turns her hair and eyes black in front of an astonished Anya.
- Also inverted in the finale, where Willow's good use of magic turns her hair white and makes her glow. That only lasts for a few seconds, though, and she goes right back to being a redhead afterwards.
- Doctor Who has "The Keeper of Traken": kind, generous, good Counsel Tremas, with his white beard, hair, and robes, sees an odd-looking grandfather clock in the middle of the room. He goes over to touch it. Oh Crap. Bad plan. It's The Master's TARDIS, and out comes the Master, cackling "A new body, at last!" Tremas de-ages, his hair and beard shortening and turning black, and gets a spiffy new black outfit. Why hello there, new Master.
- In Kamen Rider Dragon Knight, it was first played straight in dreams: first, Kit is attacked by a black-clad version of himself, and in another one, Kit dreams of taking Xaviax's Deal with the Devil and going through a second Transformation Sequence, transforming into the black suit, before hunting down and taking out his teammates. He was, needless to say, not too enthusiastic when first presented with a real-life version of the black armor.
- In Kamen Rider Kuuga, Yuusuke Godai's black Super Mode originally comes from a serious mad-on and threatens to make him a Destructive Savior. However, when powered by his sense of justice, "Ultimate Kuuga" is... still black, but the eyepieces go from black to their usual red. In Kamen Rider Decade, the black-and-gold but much more evil-looking Rising Ultimate Kuuga form, with Spikes of Villainy, is bestowed upon Yuusuke Onodera by the Legion of Doom when they brainwash him. You get the black eyes until he gets de-brainwashed, and again, they become their normal red.
- For Transformers, it's very common for Hasbro and Takara to re-release an existing toy model with a black repaint. This business model is common enough that it has its own page at the Transformers wiki which explains these change as "Spontaneous Recoloration". Shortpacked frequently takes shots at this. Often, though, the change isn't good/evil, but a powerup that leaves the character's personality alone.
- The gold parts of Takanuva's armour turn black when his light is partially drained in Bionicle.
- Samus' suit changes in Metroid Prime 3 if you get corrupted. It's implied the suit has a psychic and biological link to Samus.
- Although it's not evil, Samus' Phazon Suit in the first Metroid Prime does count, as it's her normal suit mixed with deadly blue stuff.
- In Echoes, EVERY Ing-possessed enemy. Be they bugs, bad guys, or even robots, if an Ing's in charge, expect black-and-purple enemies, maybe with Spikes of Villainy.
- When Aribeth renounces Tyr and swears fealty to Morag in Neverwinter Nights, her armor immediately turns darker in colour. (The model doesn't change, but apparently the spikes on it become villainous by default.)
- In Shadow of the Colossus, Wander's hair becomes darker and his skin becomes paler as you progress through the game, and then at the end, you become the new embodiment of Dormin, which kind of explains everything.
- Aya, the poster girl of the Japanese fan-made fighting game Hinokakera, undergoes a radical transformation when the mental blocks on her massive psychic powers are shattered. In addition to a personality change from timidity to a berserk aggressiveness, she gains a new black outfit that is much less conservative than her usual attire.
- In Mega Man Legends, committing enough cruel acts (which is difficult) turns your armour black.
- Street Fighter's Evil Ryu takes his standard white karate gi and turns it a dark shade of gray.
- In the Knights of the Old Republic games, characters' appearances change when falling to the Dark Side, include their underwear inexplicably darkening to black and switching from normal brown Jedi robes to grey-black Sith robes. Also, the Handmaiden in the second game switches from red lipstick to black lipstick while on the dark side.
- Touhou: Subverted with Lily White in Phantasmagoria of Flower View [sic]. When she appears in Eiki's stage, she's clad in black, but it's not because she's evil; she's just going along with the theme. Faeries are like that.
- Genre Savvy Dragon Age II players expected the worst when, in the game's third act, Anders' robe turned black. They were right.
- In In Famous, Cole gets more scars on his body and red lightning the more evil deeds he does. Also, it's possible to get black lightning by going full evil and making a turn to good at the last moments of the second game.
- Fate/stay night: Saber Alter. And even more notable, her master: Dark Sakura. Berserker gets the same treatment, becoming a vaguely human-shaped cloud of black tendrils.
- The Order of the Stick
- When Miko Miyazaki loses her Paladin powers, her white and blue armor becomes grey and tan. Word of the Giant says this is because the armor is magically enchanted only to work for a Paladin.
- Inversely, when Belkar gets a temporary Wisdom increase, his shirt turns white and his cape a lighter green.
- Bael from Suppression does this when he finds his hat while possessing General Victus. He decides it doesn't match his current outfit and sprouts tentacles that dye both red.
- Spoofed in Our Little Adventure, when Angelika dones a Cloak of Charisma that immediately gives her a Darker and Edgier look. Her familiar concludes that she must have turned evil.
Norveg: ... Oh great. The cloak is cursed and it turned you evil.
Angelika: I don't feel any eviller.
Norveg: That doesn't prove anything.
- Omi in Xiaolin Showdown.
- Code Lyoko
- When a Polymorphic Clone takes Ulrich's appearance in episode "Revelation", it has gray skin and a black samurai outfit with orange highlights. This is solely for the viewer's benefit of telling it apart from the true Ulrich during the following Mirror Match, since, before, the Clone had been identical to Odd, up to the color.
- William goes through a full Evil Costume Switch in "Final Round", but this is more XANA altering his avatar than a spontaneous change.
- Happens in reverse for Teen Titans' Raven: normally, she's under her father's influence but in control of herself, and her costume is dark blue, but when she's in a very good mood or completely free of her father's control, her outfit turns white.
- In the Kim Possible episode "Bad Boy", in which Ron accidentally stole Drakken's "evil energies", you could tell what the balance of good and evil in Ron and Drakken was with their skin color. Drakken's grew to be a disturbing pinkish tone and Ron's became Drakken's usual evil shade.
- When Jean reassembles all of the lost pieces of the Phoenix Force, her costume is white and gold and she becomes the White Phoenix of the Crown, the most complete Force/Host combination. However, we'd seen the outfit once before - in a flashback sequence to her after her Heroic Sacrifice at the end of the original Phoenix story. Depending on the Writer, she was, at the time, either Phoenix with a bit of Jean's soul, Phoenix impersonating Jean but absolutely completely not her, or Jean with some of the Phoenix Force in her. So...enjoy the pretty new suit and don't think too hard on it. Trust us on this one.