AFK'r
An AFK'r is a person so bad at a particular subject or skill in a certain game, that they wait until a person has gone offline, and then proceed to destroy everything they spent time on, and raid all their stuff. Their usual response to them being confronted is either "I was Bored XD" or "should've had better defense B)"
Have you heard about Adam? He apparently stole all of Michael's stuff while he was gone due to his low level weapons. He is such an AFK'r