Mud

It sounds kind of strange telling someone in Michigan that they can't drive through a car wash because their vehicle is too muddy.

Anyone that has been to a music festival knows that anything can happen.  Especially when mud is involved.  People cover themselves in it and as seen here, slide in it.  Watch and see what this goof slides into!

My girlfriend would freak out if she had to walk in a mud pit, let alone if somebody used that pit to scare the crap out of her.  Check out what happens when pranks get muddy.