Leeroy Jenkins

"Leeroy Jenkins" refers to a video capture of a World of Warcraft session widely circulated on the internet. In the clip, "a group of players discuss a detailed battle strategy while one of their number, Leeroy, is away from his computer. Their plan is ruined when Leeroy returns and, ignorant of the strategy, immediately charges headlong into battle shouting his own name as a battle cry. His companions rush to stop him, and his subsequent actions ruin the meticulous plan and the encounter ends in failure for the group. His response to the other players' reactions, "at least I have chicken", was also much parodied." (from Wikipedia)

From Urban Dictionary:

1. Leeroy

n. 1: One who does not grasp the concept of caution. 2: One whose success is based purely off relentless aggression and pure luck. 3: One who likes chicken. 4: One whose battle cry consists of their own name.

v. 1: To destroy all hopes of success. 2: To rush headlong into danger without regard to consequences. 3: To satisfy one's own desires at the expense of all around oneself. - I can't believe he just tried to headbutt that dragon. What a Leeroy.

- We were doing great until that idiot totally Leeroyed us.

- The party was really boring until Bob pulled a Leeroy.