Alright, so you'd think bringing a mattress to a show to crowdkill with could potentially be at least a little bit funny, right? I totally thought so too, and I guess it is a little bit humorous as an idea. Like, just bumping people with it or something generally harmless. Unfortunately, the guy who did it doesn't seem like he's just doing it for laughs.
Check out the video below and wait until about halfway. Dude throws a mattress at a bunch of people standing in the back, and then ninjas his way away from the situation and punches someone right in the head, who was also standing on the side. So not exactly a series of moves of someone who's just doing it to be funny.
Also, how the fuck do you get a mattress into a show? It doesn't look super well attended, but still. Mattresses are big, expensive, and heavy, so it's not like you can just go pick one up at the store beforehand.