A troll by the name of Jaffa_Africa who has, for months now, been visiting servers and mass killing his own side. He has plagued the official servers and on the private servers.
Evidence of his last mass tking:

Tking without appearing on the score board:

Admitting that he has done this many, many times before and boasting how "no one ever managed to ban me":

His banning from all servers would improve the quality of fun on those servers immeasurably.