He makes a **** of himself and then convinces himself that he's somehow right. When the facts are pointed out to him he continues to argue Black is White for pages, and then declares himself the wum master when he's owned again.
He's delusional and ****ing boring.
Perhaps a Supermod could contact his parents and ask them to have a quiet word?
.. start with advice on how not to be a sore loser and that if you make a bet you really should keep to it otherwise the other kids may think a lot less of you (putting it mildly) 
