Seriously? People getting this worked up about online politeness. Your friend's just messing with you, it's different. Not like a forum needs to be a war zone over a haircut joke.
Oh man, a wet poodle? That's brutally honest for sure. I've got a friend who does the same thing with my fashion choices. My move is to agree and amplify, like saying 'yeah, and your outfit makes you look like a couch from 1992'. It shifts the mood from criticism to just messing around. Most of the time, they're not trying to hurt you, they're just joking in a clumsy way. So give it back lightly and don't take it to heart.