Jack Nicholson took the role of Frank Costello in Scorsese's crime epic because he wanted to play "the ultimate incarnation of evil" and he makes his point by holding a severed hand and waving it at Leonardo DiCaprio over breakfast.

Costello gets more and more insane throughout the movie making him one of the most feared mobsters on our list but he doesn't go out in quite as much of a bang as the next wiseguy.