Sentient creatures, particularly magical ones, will take on the personality and/or trappings of their master. Good magical creatures will be brightly colored and soft-shaped. Evil magical creatures will be pointy shaped and darkly colored, sporting horns and/or fangs. If the creature switches sides from one to the other, the appearance will change accordingly. In short, if it looks evil, it is evil, and vice-versa.
The good/evil transition is not entirely confined to magical creatures in service. Sometimes it's a visual shorthand for the fact that a character has shaken off evil or selfish inclinations to become a good or better person; or has given in to darker impulses and gone evil.
The change from looking and/or behaving like a good entity to looking and/or behaving like an evil one is rarely something the character consciously undertakes. It just happens as their alignment on the good-evil scale shifts. When the change is conscious, the Evil Face is considered the Game Face.
Compare and contrast Evil Makeover, Monster of the Aesop, Beauty Equals Goodness; Face of an Angel, Mind of a Demon; Astonishingly Appropriate Appearance and Personality Powers, which go closely with this trope.
- When Johan is turned possessed in Yu-Gi-Oh! GX, his Crystal Beasts start looking all scary, as the Advanced Crystal Beasts. They don't enjoy it. Also, Edo Phoenix's Elemental Hero cards look dark and creepy compared to Judai's... until Judai discovers his Superpowered Evil Side, and his Heroes change looks accordingly.
- Let's not forget the Monster World episodes of the original manga, where monsters Yugi tames become cutesy and cartoony.
- YuYu Hakusho: when Yusuke is resurrected the second time, this time under his own power as a powerful demon via the Atavism of the Mazoku as a descendant of Raizen, Puu changes from something that looks like a small stuffed penguin to something that looks like a very large phoenix, which people can ride on.
- Mobile Suit Gundam 00 has the Haros, which are adorable robots which are clearly at least partially sapient. While those owned by Lockon and the Bridge Bunnies are friendly and playful, that owned by Nena Trinity has red eyes and a nasty/cruel sense of humor.
- This is Wigglytuff of Pokémon. This, on the other hand, is Harley's Wigglytuff.◊ Suddenly a lot less cute when used by a Jerkass trainer.
- Since the start of A Triangleinthe Stars, Bill Cipher has been wearing a demon face, obviously. Harsh, quick to anger, arrogant, sociopathic and insensitive, etc etc. His physical features even reflect this. However, it started to change, and ultimately, in Chapter Thirty-Two he starts reflecting more of an angel face.
"His expression was a lot softer than it had been, like an enormous weight had been lifted off his shoulders, and there was a subtle warm glint in his eye. It made his hellish pupil seem unnatural now..."
- In Off The Line when Vincent was a boss mob, his head was circled with jagged horns and had claw-like hands with leathery wings. He was a Eerie Pale-Skinned Brunette with visible veins on his skin with his hair covering his face, giving him a very demonic appearance. As a pet mob, he's nearly indistinguishable from a human besides his wings as he loses the horns, the veins, the paleness and his face is visible.
- The Big Blue Genie in Disney's Aladdin begins the movie as a playful, googly, shape shifting whack job. But when his lamp came into the possession of Jafar, his coloration and body shape changed to the "evil Djinn" stylistic (Only temporarily, because once Jafar gets magical powers and is able to do the evil things himself, the Genie doesn't need to look intimidating and reverts; then later Jafar becomes a Genie and its appearance is an Evil Counterpart - red, muscular and with Villainous Cheekbones in contrast to the blue, chubby and overall rounded)
- Likewise the Beast in Beauty and the Beast undergoes changes in his appearance that's directly tied to his Character Development. The filmmakers even admitted this and while he remains recognizable as the same character throughout the film his design goes from angular and inhuman to a much softer and appealing look later on.
- Lightning McQueen from Cars starts out as an arrogant, stuck-up snob who only cares about winning and the victory that goes with it. Over the course of the movie, his attitude slowly softens as he discovers there's a lot more to life than just racing, and by the end of the film, he's become a full-on Nice Guy who's kind, caring and selfless.
- Darla Dimple from Cats Don't Dance could turn this transformation off and on at will, so she appeared as a cute little curly-topped moppet or a demon child depending on her mood and whether she thought anyone besides her butler was watching.
- Bartok the bat from Anastasia starts out a little sinister, but is downright cute by the end of the movie when he's given up on serving Rasputin.
- In The Spiderwick Chronicles, the boggan turns into a boggart when he's angry. He's not quite evil, but he's less friendly, more malicious, and stops rhyming as well as taking on a much scarier appearance.
- Interesting subversion in Howl's Moving Castle, in that Sophie's appearance definitely changes according to how she feels about herself. When she is happy and self-confident, she is beautiful and her features are soft. When she thinks she looks ugly though, her features resume the "old hag" look of her curse. In a way it could be seen as the viewer seeing through Sophie's eyes, the idea being that if you feel beautiful, you see yourself as *looking* beautiful too.
- A subtle example in Ratatouille. Anton Ego looks cadaverous and evil until the very end of the film, where he appears to have gained some weight and lost his ghastly pallor.
- The Emperor's New Groove: Titular character Kuzco begins the film selfish, spoiled, tactless and lacking in consideration for anyone not himself. His features are smaller and more angular. By the time he is restored from being a Llama, his features are softened and he playfully pretends to be the same arrogant child.
- Moana: Maui is all harsh features at the beginning of the movie. But starting with his confession about his past, his features begin softening. He's practically cherubic by the end of the film.
- Enchanted: The mundane and ordinary Nathaniel, while still serving evil sorceress Narissa, is all disheveled and shifty [exploiting actor Timothy Spall's ability to look uncannily like a rat]. But once he realizes he's been used, turns on her, and becomes a real friend to the prince, he becomes all tidy and dapper.
- Bob the Skull in The Dresden Files is a variation. His appearance doesn't change much, since he's a spirit occupying a human skull. His personality, however, is affected by the wizard he serves: his usual wise-cracking and lecherous but ultimately benevolent and helpful personality is a result of his serving Harry Dresden, who is a fundamentally decent person. Harry got a glimpse of Bob's personality under more evil wizards. It wasn't pretty: Just reviving the memory of his time serving a truly evil wizard, and Bob very nearly killed Harry in cold blood.
- The colour of his real form (a cloud of sparkling motes which can be seen through the skull's eye sockets) does change under these circumstances — from a warm orange to a cold blue.
- The Djinn in the Weather Wardens series by Rachel Caine are all pretty tricky and ill-tempered, but how much is tempered by the Warden the Djinn serves, and how human the Djinn feels like looking at any given moment. Joanne the fashion plate, once entering servitude to Lewis, ends up in jeans, hiking boots, and flannel, and cannot change the outfit because that's what her master thinks of as appropriate work clothing.
- Detective Inspector Chen series: Inari, Chen's wife, is a half-human demon. While on earth or the near-earth levels of Hell, she looks mostly like a beautiful human woman. But when she descends into the lower levels of hell, she becomes more demonic in appearance, to the point of her fangs and forked tongue making it hard for her to speak. This is a subversion of the trope, because even though she becomes more demonic in appearance, she retains her sweet and gentle personality; in fact she rescues someone from what would have been an inescapable trap because she had genuine pity for his plight and Hell denizens are not known for their sympathy.
- Your monster in Black & White becomes cuddly and fluffy or sharp and fanged, depending on whether you train it to act good or evil. Your hand (all that you can see of yourself) likewise changes according to your actions. interestingly, your monster can have the opposite alignment to you with no drawbacks.
- Another example is the genie in King's Quest VI, who takes on the personality characteristics of his master (and the game remarks on this explicitly). When he serves the Vizier he is shifty and homicidal, whereas when he serves Prince Alexander at the end he's almost too sweet.
- In The Legend of Spyro: A New Beginning, Cynder turns from a huge badass spiky dragon into a small cuddly baby one as soon she leaves the influence of the Dark Master.
- In Mass Effect 2, Shepard's reconstruction scarring becomes better or worse depending on the player's Paragon or Renegade scores. All the way Renegade and Shepard's eyes turn red, with glowing orange cracks all over his/her face. However, a player can buy an upgrade to remove all scars, regardless of alignment.
- In Joy Mech Fight, each of the first eight robots you defeat is then reprogrammed to the side of good. This process also changes their color and design.
- In The Legend of Zelda: Twilight Princess, Princess Zelda becomes sickly pale, gets glowing yellow eyes, and starts developing blackish veins around her face and neck after she's possessed by Ganondorf.
- In Chrono Cross, Pip changes his appearance based on whether you use predominantly Light or Dark Elements in battle, becoming more "angelic" or "demonic".
- In one The Sims 2 expansion pack, witches change appearance the more good or evil spells they use. Good witches are sparkly and wear white, evil witches are green-skinned and wear black. Neutral witches apparently wear brown.
- Knights of the Old Republic has the player character's eyes turn into slits, and the skin becomes pale and wane the further towards the Dark Side you go. Honorable Jedi look proud and haughty.
- In the sequel, this happens to your party members as their alignment changes.
- Sonic Adventure 2 gives us the page image. Specifically, when Chao in the Chao Garden are primarily exposed to good characters like Sonic, they become angelic, and when primarily exposed to evil characters like Shadow, they become demonic.note The difference is purely cosmetic.
- The Fable series shows an incredible difference between good and evil player characters. Unfortunately, it is incredibly easy to switch between alignments. If your halo-sporting goody-two-shoes eats enough live chickens, he'll turn into a (very fat) horned monster with dry, pale skin. Then all you have to do is donate enough money to the temple, and you're back to that glowing aura of Incorruptible Pure Pureness.
- inFAMOUS does this too. Being good makes your clothes brighter and your lighting a cheerful blue. Being evil makes your skin and clothes turn black and white and your lightning a bloody red. The sequel ups this. A good character's scar fades and his Amp (a club-like weapon Cole charges with electricity to beat people down with) becomes a shiny chrome, while an evil character scar gets worse and his Amp becomes rusted.
- Cosmo and Wanda, The Fairly Oddparents, don't quite manage to subvert the trope. When they are forced to serve Denzel Crocker they look the same [but he's just insane]. They also appear the same when they serve Vicky who is pretty universally considered evil. Cosmo and Wanda do, however, grow goatees on their own "day of evil". They also have the anti-fairies, who look like them except colored dark blue, and possessed of fangs, bat wings, and pointed ears.
- Tom and Jerry both display angelic or demonic features based on their behavior and/or plans against the other, even unto growing the horns and tail.
- Dante's Inferno: An Animated Epic - When Dante Alighieri (yes, that Dante Alighieri) starts going batshit insane from the horrors and stress of the three year Crusades.