Buy him a carrot, put it in a present and leave it with the other presents. Act like you thought it was his mom's birthday when he sees it.
That's cute and I would do that but I'm not going to any stuffty birthday party, I just want to put something snappy on his facebook wall.
Well, judging by his description, you'll create a downward spiral of tit-for-tat pranks and arguing between each other that'll make you both miserable. But if you still think "revenge" will solve something go ahead.
He's the kind of guy that would delete them after he looses. I'll get you pics of what I mean.
you're an starfish
No dude, you took that the wrong way. He is scrawneyer than how boltster thought you where. I'm not calling you scrawney. It's an example fuuuuuu :c