This is interesting but I just want to add you really want to be certain with your symptoms. Because lots of different idea's come up as possibly problems...    And hopefully people will think before they read into it...

I did a little search and one of the things that came up was lead poisoning and that was from just checking his behaver change... But that is ok, I know he does not have lead poisoning he is just being a two year old boy who does not want little kids to take his cars from him... :)