Evil Twin/Playing With

Basic Trope: A character has or encounters an evil duplicate.
 * Straight: Bob encounters Evil!Bob, his evil twin.
 * Exaggerated: Bob has two evil twins.
 * Downplayed: Bob encounter Jerk!Bob, his Jerkass twin.
 * Inverted: Evil!Bob encounters Good!Bob, his good twin.
 * Parodied: Both twins are evil.
 * Subverted: Bob's supposedly evil twin turns out not to be evil.
 * Double Subverted: Evil!Bob was just playing a mindgame with Bob. He's a monster right to the core.
 * Deconstructed:
 * Reconstructed:
 * Zig Zagged:
 * Averted: Bob doesn’t have an evil twin.
 * Enforced: The writers want to create a new enemy for Bob, but are convinced he needs to be a much more personal nemesis for Bob than his previous adversaries.
 * Lampshaded: "So you're my evil twin, huh? Then where's your goatee?"
 * Invoked: Someone (perhaps even Bob himself) intentionally uses Applied Phlebotinum to create an evil twin of Bob.
 * Defied: Bob's identical twin is prophesized to become his evil counterpart, so their parents do everything to instil Evil!Bob with kindness and good virtues.
 * Discussed: "Bob has just discovered his identical twin. I'm telling you the guy must be evil or something, no way around it."
 * Conversed: "In this episode Bob runs into his evil twin."