Durial321 was an infamous rule-breaker, most well known for his part in the Falador Massacre of the 6th of June 2006.
During the Massacre, caused by a construction glitch allowing certain players to attack and kill others outside of the PVP areas, Durial321 killed numerous players around Falador. He was eventually kicked from the server by a Runescape Mod and then permanently banned. He is said to have caused victims to lose over 1 billion coins worth of items and cash, as well as looting a green party hat. Videos of his and others' tirade, surounded by a crowd cheering him on with numbers nearing the hundreds is widely available online.