Lions center Dominic Raiola stomped on Bears defensive lineman Ego Ferguson's ankle at the end of a play when Ferguson was down. The stomp looked completely intentional:
Ferguson limped off the field, but came back into the game on the Bears' next possession. Earlier this season, Raiola went for a Patriots player's knees on a dirty play.
As ProFootball Talk points out, when Ndamukong Suh stomped on a Packers player in 2011, he was suspended for two games.