How do I deal with this guy who OBSESSIVELY likes me? 10 pts? DESPERATE?!?!?

[Ska]

This guy is annoying, but he's not stalking you (I don't know what you mean that he "stalked" your Facebook profile -- to me that sounds like a super melodramatic way of saying that your privacy controls weren't properly set, so he found and read your profile), and I think it's a bit much for you to be calling him "obsessive" and "desperate" after, what ten days? But, still, there are some things you should and could do to cut this off.

1) If you have any gifts he gave you that you have not yet returned, give all of them back immediately. Leave them in a garbage bag by his locker or car. If he tries to buy you anything further, don't even accept it.
2) Stop engaging him in conversation, period, in person or online. DO NOT SPEAK TO HIM. He'll probably have a new love of his life by the middle of that afternoon.
3) Report him to your school authorities IMMEDIATELY.
4) Block him on FB (I mean, come ON!) and change your privacy settings so that you can't be found by any idiot who feels like looking you up. Tell your friends what is happening and ask that they tighten up their privacy settings so that he cannot view your profile through theirs.

Do NOT do the fake boyfriend BS. You're having drama with a weirdo -- it's not right to pull a third party into that. Besides, you need to make it clear, the same way you would with a breakup, that it's him you aren't interested in. You don't want to send the message that if you weren't attached, you two might have a future.