How to deal with a one upper?

[Sabretooth]

This reads like the perfect opportunity for a "mental bye Felisha ".
The guy may enjoy bugging others and if so will continue that behavior.
Ignore him when not necessary to interface with him on work related projects.
Hoping he gets fired or burns out maybe fruitless. Don't go postal.
Discuss with his boss the disrupting work habits, perhaps the boss will define his job parameters and expectations.
Don't waste any mental energy fretting about him ( that may get under his skin, which is a good thing - I'm big on passive revenge )
When you go to the bathroom you can name your bowel movements after him ( for a secret chuckle ).
Don't let him live free in your head- that is valuable property