A Smash Mouth concert in Colorado turned into an ugly confrontation between the band’s lead singer, Steve Harwell, and the audience. EW.com reports that Harwell went into a rant during the show at the Taste of Fort Collins festival, all because fans were throwing bread on the stage.

Harwell launched into an expletive-laced series of threats against various audience members, then climbed down from the stage and went into the crowd. He was restrained by security, but continued his verbal rant.

As Harwell taunted the audience, the band led fans in a singalong version of the groups monster hit, “All Star.”

The incident was captured in a number of videos recorded by fans, several of which have been posted on line. Here’s one example, which carries a warning about explicit language: