The rarest penalty in NFL history.

From the NFL Rulebook on a palpably unfair act: A player or substitute shall not interfere with play by any act which is palpably unfair. 51 Rule 12 Penalty: For a palpably unfair act: Offender may be disqualified. The Referee, after consulting the officiating crew, enforces any such distance penalty as they consider equitable and irrespective of any other specified code penalty. The Referee may award a score.