My cat Miles has always chased his tail when hyper since he was a kitten. He is now going on 8 and still does it. He used to not make much noise when doing it, except when he bit it good and then he might growl. Over the past year though, he has added an odd twist to it. He has started hissing and growling when doing it all the time. Most of the time he doesn't do it all that much, but sometimes he gets quite intense and its like he's getting in a fight with himself. He isn't damaging his tail or anything, but I just thought it was kind of strange for him to get so aggressive just chasing his tail. Is this fairly common ? Or just another case of Miles being a one of a kind weirdo ?