What's your favourite role to roll antagonist for, and why?

[Mouse]

My favorite role to roll antag on (as opposed to my favorite antag type) is clown.  You can get away with a lot of stuff as an antag clown if you can find the right balance of humor and deadliness!  I once murdered the captain with a c-saber and did it with such clownish style that the captain, after being cloned, demanded that security release me and give me my c-saber back.