Rose Monday Carnival in Germany, but why the Clowns?

I am not German nor live in Germany, but this looks like so much fun. Why they have papier-mache heads of people dressed in clown is unknown to me. If you happen to know please tell me.

As is the German carnival tradition, individual Schwellkoppe (“swollen heads”) or larger-than-life-heads made from papier-mache march with bands in between the floats.

These clowns all look pretty creepy. Who do they mock? Local politicians and businessmen? The three in the front all have the same metal emblem around their necks. What is this?