Apparently, Kris' frustration over Rob's performance had grown during the last couple of weeks and culminated this show when the band's performed Your Boyfriend Sucks. During the song's bridge, Kris suddenly took off his guitar and threw it at Rob, who initially continued drumming.

Next, Kris began to throw pieces of the drum kit toward the rear of the stage, before stating to the audience:

"Our drummer's fucking failing it tonight, I don't know what the fucking problem is but I'm gonna finish the set by myself. I'll play a few songs, whatever you want to hear but I can't fucking do this. Sorry, sorry. We all have bad shows but it's fucking embarrassing, I can't handle it. I apologize but there's a certain amount of fucking shit I can take, but, ah, rock and roll"

The attacked drummer decided to call it quits, tossed his drum sticks away and walked off. The rest of the band followed Rob off the stage. Kris proceeded to throw the last bits of the drum kit, most notably the bass drum, and continued the show by playing audience requests on his own.

Watch video footage of the violent outburst on-stage below. Around 4:50 things get really nasty and Kris goes kind of mental:

Here's the same stage tantrum from a different angle:

Not surprisingly, drummer Rob has quit The Ataris.

The band minus drummer issued a video explaining why Kris flipped out on stage. According to this statement, the drummer had been drinking heavily before the show and was a mess on stage, missing beats and playing like crap: