You can punch and burn him without killing him. You can torture him whatever, however you want. You can be his best friend and play with him. (So far, I think he loves rubber balls.) You can even change him to a Teletubby or Bill Gates even. Still I like him as Buddy and even without a face, I feel for him.
Unleash the evil or goodness in your heart onto him. He won't really be hurt.
After playing this game, I realized I don't like hurting him. I'd stick to the rubber balls and tickling but then again I get curious with the other items. Happy playing! :)