Tony Stewart did it: He stepped onto the pit road at Bristol and chucked his helmet at Matt Kenseth.
What happened since show how dumb Stewart was in that angry moment nearly four years ago.
Sporting News detailed the incident, which occurred during the August 2012 night race.
Stewart and Kenseth were racing for the lead on Lap 332 when they got together on the front stretch, sending both cars spinning into the inside wall.
Angry at the contact, Stewart flung his helmet at Kenseth's car under caution. Stewart then turned to the crowd with a fist pump to get spectators excited.