Katt Williams Throws Sucker Punch ... Gets Stomped

Katt Williams had a crazy night in Philly ... bum rushing the stage at a rap show, punching a guy and ultimately coming up on the losing end.

It all went down Sunday night at the Trocadero Theatre ... where Beanie Sigel, Jahlil Beats, Jadakiss and a few other rappers were performing.

Williams was all over the place ... freestyling onstage, randomly doing pushups and standing around in a fight stance for no reason.

Williams suddenly ran full speed at someone onstage and clocked them. The dude he decked had a loyal entourage ... which beat Williams down.

No one was arrested.

Williams has had an interesting few days, to say the least. He was arrested last week in Georgia for allegedly punching a store clerk ... a day before that, he allegedly held five women at gun point ... and then a few days later he got into a fight on the streets of Los Angeles.