The Detroit Pistons' lousy season somehow just got even lower ... the team's GM, Troy Weaver, was filmed getting into a heated spat with an angry fan at a game on Saturday.
The incident reportedly happened in the fourth quarter of Detroit's blowout loss to the Dallas Mavericks at the Little Caesars Arena ... when a man decked out in Red Wings gear seemed to confront Weaver at his seat.
You can see in a video posted to TikTok on Sunday ... Weaver appeared to yell at the fan, "You're lucky I don't beat your ass" -- before the man can be heard responding, "You suck at your job.