Saw something like that happen last year at a show at the EARL here in Atlanta, but it was the entire band self-destructing -- not just one or two jerkasses.
We were headlining, and the opening band was from Houston and had been on the road for a while, apparently. Things seemed cool during load-in and soundcheck. But the instant these guys got on stage, it was WWIII.
They were a 4-piece w/ 2 gtrs, bass, drums. They made it through 2-3 songs, and then Guitarist/singer #1 starts getting visibly pissed. He says something inaudible to the drummer, and this gets the drummer going. They make it through 8 bars of the next song and it breaks down. At this point, the drummer throws a stick at Guitarist/Singer #1. He throws it back at the drummer. They proceed to get into a cursing, yelling, verbal fight.
Bass player and Guitar #2 are just staring, slackjawed. Guitarist/singer #1 has a girlfriend in the audience -- she's yelling at them like their football coach: "Just play the songs! Play the G-D songs!" The audience is looking around at each other like "DAAAAAMNNN! I didn't realize my $6 cover got me admission to UFC fight night!". It was quasi-uncomfortable to watch, but at the same time it was compelling and pretty damn funny...
So they try the last tune again, and almost make it past where they died before. But things fall apart again, and G/S#1 throws down his axe (which must've happened frequently judging by the amount of duct tape on it...) and storms offstage.
Thus endeth the Atlanta date for those cats.

It was pretty lame. I mean, I had no idea they were even f-ing up songs. But apparently it was so bad to them, they had to go nuclear about it. I felt bad for them, but not too bad. We went on early, played 20 mins extra, and had a great long set. A splendid time was had by all (except the other band, I guess).