During Arctic Monkeys' Friday night headlining set at Lollapalooza, a man was bitten by some random guy.

Ben Lenet, 29, explained what happened on Reddit.

"The incident: Me and two other friends are enjoying the show and have even made some friends around us. The mood of the crowd is really happy and a nice departure from the normal drunken debauchery. Suddenly, I turn around and some guy none of us have ever seen or spoken to, without warning, body slams my friend and begins using his hands to choke him. My other friend begins hitting the assailant in the face. I come from 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 5 seconds. He’s not nipping at me. He’s trying to bite through my arm. At this point, all three of us are hitting him, trying to get him off me.

Finally he lets go and lunges at the feet of the original bodyslammed-friend, trying to bite him too. He is then kicked pretty squarely in the face.

The attacker has now taken 10-15 blows to the head and been punted in the face. He gets up and walks away. Not stumbling. Not woozy. He just fucking walked away in a straight line. CPD would later tell me they only see assailants like that who are on PCP or bath salts."

If you want, you can see photos of his arm here.  He was bitten pretty hard.

The Chicago Sun Times reports that Lenet has heard little from Chicago Police since the incident.  The cops have nobody in custody.

Lenet is trying to use fellow Redditors to get more information on what happened.