It never happened to me but I would respond as follows.
That jerk needs to learn how to be a good loser. I doubt it will happen though. Personally, I liked your invatation to the 'Dark Side' idea. Congratulations on your win.
When you block a person, they can no longer invite you to a private message or post to your profile wall. Replies and comments they make will be collapsed/hidden by default. Finally, you'll never receive email notifications about content they create or likes they designate for your content.
Note: if you proceed, you will no longer be following .