Wow! I can't believe all the replies already. Thank you all. I should clarify: It's not so much his energy (guess I put that in for background) as it is his sudden attacks. It's the biting and scratching that we'd like him to stop. There are 5 cats here (2 are mine) so he doesn't need a playmate and we play with him often as well. He attacked my friend the other night for no reason. Ran up to her, wrapped himself around her leg, and bit and scratched her so hard he drew blood. He's also been attacking my other cat. They've been together about 2 years without much problem. The other cat has always been the alpha male, but Scooter seems to be challenging him now. Hopefully, age will mellow him.