it doesnt mean he is "going to get mean" hahah,is he shedding ? ususally when there eyes start to cloud over they will strike at anything that moves.Did you have mouse scent on you at all ? maybe he smelled food on you ? do you feed him in the tank ? people say that if you feed them in the tank that the snake will associate the opening of the cage lid with food,thats why i feed mine out of the tank and i ave never had a problem.And dont be scared of the bite it doesnt hurt.