Game: Batman: Arkham Asylum
What Makes Him Bad: A complete and utter disregard for human decency. Everything's a joke to the Joker—especially killing Batman.
What Makes Him Cool: Mark Hamill makes the Joker come alive, no matter what craziness he gets himself into.

The Joker—arguably more of a comic book villain than a video game one—his mind games, vicious moves, and wicked personality make his antics a blast to follow, even when he's knocking on death's door. Arkham Asylum and Arkham City were fabulous playgrounds for the devilishly debonair clown in the purple suit to exercise how insane he truly is, and we're all the better for it.