The "Gretzky rule" in the National Hockey League refers to a specific regulation implemented to penalize players who take off their helmets during a fight. Established during an era when on-ice altercations were frequent, the rule mandates that any player who intentionally removes his own helmet prior to or during a fight receives an extra minor penalty on top of the standard fighting majors. The rule was colloquially named after Wayne Gretzky because he had a famous habit of quickly sliding his helmet off before engaging in rare scuffles to protect his head or avoid damage, prompting the league to crack down on the practice for player safety.