It's unclear exactly where it went wrong between Young Thug and Rich Homie Quan, who were once so close Thugger called RHQ his hubbie.

But they've been snipping at each other for the past year.

Thug fired the latest shot during a show in Santa Ana, California. As the intro to the Rich Gang track 'Lifestyle' played, Thugger began casually repeating "Hey, fuck Rich Homie."

We're a bit surprised Thug wants to keep whatever feud with Quan he has going. Since they've parted ways, Thugger has become one of the most famous (and polarizing) emcees in the game, whereas Quan is flying coach.

While they say the best revenge is living well, apparently Thug can't leave it at that.