The TzHaar Fight Pit massacre was an event that occurred on the 13 May 2008, and was the result of a glitch. It happened in the TzHaar Fight Pit, which is supposed to be a safe minigame. However, some players discovered that they could attack and kill other players who were in the waiting room. Anyone who died lost all their items.
Jagex fixed the problem the same day. They also issued lengthy bans to players who had killed other players by abusing the glitch, under rule 4 of the Rules of RuneScape, which states: "You must not use or attempt to use any cheats or errors which you find in our software."