I still remember my first Butthole Surfers concert. When the band came on and started playing, the people started to twist, turn, and jump around while bouncing off one another.
At first it was fun, there was even one very hot girl that kept bouncing and bumping into me. In turn, I started bouncing and turning back into her. Suddenly something hit me in the back of the head, I think it was an elbow, I turned around and saw a big angry guy bouncing around looking at me, the girl bounced into me again, in a very pleasing way, then this guy jumped and twisted his elbow across my mouth.
Around me the people all seemed to raise all their elbows up a bit, some smacked this guy, who then smacked other people. Next thing I knew there were elbows flying everywhere. It was not so fun anymore.
As my vision got blurry, I felt there should have been a a sign "Caution Mosh Pit".