Gilbert Arenas and Javaris Crittenton
This is one of the most infamous sporting rivalries because these men didn’t hold back. The Wizards teammates flew to a road game on a chartered flight where they played a card game and gambled. Arenas allegedly won but Crittenton refused to pay him. They threatened to shoot each other but nothing happened and their teammates thought it was over.

However, that wasn’t the case because the bitter enemies pulled handguns on each other in the locker room. It almost escalated to a point they couldn’t return from. Luckily, teammates defused the situation but that wasn’t the end of the story. The NBA suspended both men while Crittenton is now serving time for manslaughter (via Sportskeeda).