How to cope with him? Ignore him. I know that his a simple reply, but I once dealt with a coworker who was manipulative and tried to get under my skin (successfully) for 7 years. It was hell. If I had just ignored him and had kept my eyes on my own paper, so to speak, I would have avoided a lot of mental anguish. It's really hard, but it's probably the best solution. (And sometimes people are just looking for a reaction...don't give it to them. They'll eventually stop.)