Bad sportsmanship story

Mike Tyson
The rematch between heavyweight boxers Mike Tyson and Evander Holyfield ended in disgrace as the former bit out a chunk of the latter's ear.
In the first bout Tyson complained of repeated headbutting and he felt it was happening again in the second.
So in the third round he took action and bit off a chunk of Holyfield's ear. The referee noticed and docked him two points - but had to call of the fight after he tried to do it again.