Bill Romanowski and Marcus Williams
Some teammates have passive-aggressive rivalries but others turn violent. That’s exactly what happened between these bitter enemies when they played for the Raiders. The pair argued on the practice field when Romanowski ripped off Williams’ helmet. Then he brutally punched him in the face.

Williams’ career came to a premature end after the incident because it was unsafe for him to continue. He successfully sued Romanowski for over $400,000 as he showed why violence doesn’t pay. Romanowski was one of the dirtiest players of his era but usually his opponents felt his wrath, not teammates (via USA Today Sports).