The cake that the town brings to offer Cartman changes from a large three tier cake with a #1 on top and Eric written on the side of it, to a much smaller two layer cake with four candles on top.
When Stan comes back from the stage to his friends, Kyle's saying something but no sound is heard.
Cartman intends to drive the hippies away by playing 'Raining Blood' by Slayer, reasoning that hippies can't stand Death Metal. Actually, Slayer play Thrash Metal.