When a couple Zombies enter a big rave and start attacking all the humans and eating there brains. Then the attacked humans become zombies. And those zombies attack more humans.
See It's a never ending cycle intill the whole Rave becomes one big Zombie Rave Party.
Jimmy: Oh Sweet Jesus, would you look at that.
Karen: Looks like another Zombie Rave Party to me.
Jimmy: LET'S JOIN IT!