An attendee at last weekend’s Lollapalooza festival in Chicago was bitten by another unidentified attendee. The victim is now seeking the public’s help in finding his attacker.

According to a post the victim put on Reddit, the attacker came after two of the victim’s friends during the Arctic Monkeys’ set at the festival on Friday. “Suddenly, I turn around and some guy that none of us have seen or spoken to, without warning, body slams my friend and begins using his hands to choke him,” the victim wrote. “I come to the other side and place my right arm on his right arm and my left arm on his right shoulder, trying to pull him off. The attacker then turns his head and clamps his teeth into my arm for a good five seconds. He’s not nipping at me. He’s trying to bite through my arm.”

The victim described his assailant as being 5’7″-5’11”, dark-skinned (but not black), and between 170 and 210 pounds. Police have told the victim that his attacker’s behavior is consistent with that of people who have taken PCP or bath salts.

Anyone with any information about the incident is asked to contact the victim on Reddit.