Hey, look ma, it's a mosh pit! Guess what? There isn't one guitar, singer, or sound of metal greatness to be found. Apparently, moshing to dubstep is a thing? 

And so is getting knocked the F out by a random rave stepping, wanna-be mosh pit, arm flailing dude who obviously is upset about something, keep an eye on his chest.

Punch throwing bloody guy's anger at :18 is clearly evident and guy on the receiving end doesn't see it coming, nor does the chick who witnessed the whole thing go down. Boom!

In the words of Chris Tucker from Friday, you got knocked the F out!