I have a two year old neutered male cat, Sinatra. He is a bit crazy and does odd things all of the time, but today he did something that was very odd. He was dragging his bum on the carpet and pulling himself forward with this front legs. I checked his bum and there doesn't appear to be anything wrong from what I can tell. Is this normal (or at least semi normal) behavior or should I take him to the vet to have him checked out?