Game: The Secret of Monkey Island
What Makes Him Bad: Scheming, terrorizing, and otherwise haunting Guybrush Threepwood and the rest of the cast in order to get to the Governor.
What Makes Him Cool: Arrr, that pirate booty, horrifying face, and pirate outfit.

LeChuck is one of the worst kinds of villain because he can never truly be conquered. He's out to make Governor Elaine Markey his, and in the process has transformed into a ghost, zombie, and even a boring old human, coming back to terrorize Guybrush Threepwood and the citizens of Melee Island indefinitely. Let it go. You've been permanently friend-zoned.