Lil Yachty's Bodyguard Brawls at SXSW

Lil Yachty's crew got into a brawl at SXSW ... with themselves.

We got video of Yachty's bodyguard beating down a guy who is part of the rapper's entourage ... or at least he was. The fight went down Friday at the Omni Hotel in downtown Austin.

The clip starts with punches being thrown and Yachty standing nearby and watching the action unfold.

Law enforcement sources tell us police responded to a disturbance at the Omni, and investigated a fight in the lobby. The dude who got crushed is reportedly Thouxanbanfauni, a rapper who's been Twitter beefing for days with Yachty.