Chaotic Stupid

A D&D (or other similar system) character who uses their chaotic alignment (usually chaotic neutral) as an excuse to do whatever they want, even if it's obviously a lethally bad idea, will piss off the other players, is extremely out-of-character, or a combination of the three.

DM: You see a large corridor with a desk at the end.
Player 1: Whose desk is it?
DM: The nametag on the door behind you said "Planetar General".
Player 2: I shit on the desk.
Player 1: Dude no don't you'll get us killed.
DM: Are you sure you want to do that?
Player 2: My character is chaotic neutral, and as such would do this very stupid thing for the sole reason of causing chaos, regardless of consequences or how anyone else would react.
Player 1: More like Chaotic Stupid.