Here we have Alice and Bob. Bob is a friendly enough fellow, Alice is not involved in any criminal activity, etc. And here we have Mary. Mary can be The Vamp, the Femme Fatale, the Dragon Lady, etc. Dating Catwoman might apply here. Even if not an outright antagonist, Mary can still be the Veronica to Alice's Betty, the Dark Action Girl to Alice's Action Girl, the Lady of Black Magic to Alice's White Magician Girl, as well as being the Lovable Alpha Bitch, the Broken Bird etc. There may or may not be a confrontation between Alice and Mary. Who ends up with Bob varies. Western Animation
- In the King of the Hill episode "Bad Girls, Bad Girls Whatcha Gonna Do", Connie's family takes in her delinquent cousin, and Bobby falls for her, intrigued by her dark rebelliousness. He unwittingly helps her set up a meth lab.
Hello, Unknown Troper. You'll need to get known to lend a hand here.