The Evil Doppelgänger is traditionally a Mirror Universe counterpart. The double can also be the equivalent of For Want of a Nail: he/they represents what the hero or heroes could become, or may become. Sometimes the evil double is a clone and may brood about how he's not a "real" person, just a hollow imitation of the original. If that happens, the clone tends to go mad and try to murder the original to take his place. The evil doppelgänger is not to be confused with the original doppelgänger. This character is more like the Evil Twin. See also Criminal Doppelgänger and Evil Counterpart.
Types of evil doppelgangers include:
Anime & Manga
- The Copy Rockman/Copy Robot from Mega Man Megamix is a good example. He's a copy of Mega Man that believes himself to be the real one and has his memories, but then he goes and tries to kill Dr. Wily. This helps to prove that he's not the original, due to the whole Thou Shall Not Kill thing. He's more powerful than the original, but has a defect that can overload and destroy him, guess what happens in the end. When Copy Rockman finds out he's a copy created by Wily, in the end he commits a Heroic Sacrifice to save everyone from Bass and his own destruction.
- Sonic The Hedgehog The Movie had Metal Sonic act like this, that is until his final moments.
- Magic Knight Rayearth had Nova, who apart from Pointy Ears (and a Slasher Smile...) looks a lot like Hikaru. She's actually the personification of Hikaru's guilt and despair.
- Mewtwo from Pokémon: The First Movie franchise may count. He does eventually do a Heel-Face Turn of sorts.
- One of these is featured in the Phineas and Ferb fic PnF: Stolen Identity though the origins of said doppelganger are never properly explained.
- Star Wars has Emperor Palpatine as the Evil Counterpart to Master Yoda.
- Godzilla has two: Mecha Godzilla and Space Godzilla.
Live Action TV
- In Saints Row IV you have to face your character's evil doppelganger, who has an evil eyepatch and a goatee (even if your character is female).
- In The Inexplicable Adventures of Bob!, Galatea is an emotionally unstable, sometimes dangerous clone of Molly, but it would be unfair to call her evil. "Chaotic" though? Sure.