Killerball is a futuristic Action/Sport game developed by Microïds in 1989 which blends American football with roller-skating. This violent game is played in a circular rink where each 5-man team tries to score by putting the ball into the hole of the opposing team. Taking the ball from an opponent can only be done by knocking him down.
Atari ST intro screen of Killerball
Killerball is also the name of a sport that blends rugby, American football, football (soccer) and hints of others, developed in England by those behind the 'code of crunk'.