My cats play rough and wrestle and bite each other but they're really just playing. Storm doesn't seem to like Cirrus and has been chasing him under my bed several times a day. Sometimes he chases him into my bathroom and he'll stand guard outside the door. If he gets too close to Cirrus then Cirrus will hiss and growl at him. I don't know if it's just a strange game Storm's playing or not. Storm is the alpha cat and very proud of it so he's very proud of himself when he's able to chase Cirrus under the bed.