I'm going to embarrass my friend
I'm struggling to understand why you would want to embarrass your friend?
He is a bad person and I think that's what he deserves.
I would argue doing that to a friend makes you a bad person yourself. It's actually quite rude to embarrass someone regardless of if you know them or not.
I really don't care, I just want him to feel bad.
If you want him to feel bad and hurt him, then maybe you need to evaluate if he is your friend or not. You should stay away from him if he makes you feel such negative feelings, instead of trying to hurt someone.