The evil moshing starts with too many people in a room that's too small. Then the crowd starts to sway. Some of the larger people in the crowd decide to push people out of their way. The other people who push back create a chain reaction that initializes the evil mosh. The frothing frenzy has begun.
Bodies hurl themselves against each other, and eventually the evil mosh wears itself out.
Then the magical mosh sneaks its way into the heart of the crowd. The crowd ceases being a group of people, and evolves into an organized and cohesive living thing. I am not joking. It is born and it dies. At the beginning, there is music.