so recently, as i was putting my hand into my snake's cage to change his water, and he bit me! this was the first time he had ever done so. it was just a quick bite. he didn't latch on or anything, but it was still unusual for him to do so. i had just taken a rat out of the freezer to thaw, but it was in a bag, so im not sure if my snake would have been able to smell it's scent on my hand. i just assumed that there was a smell that triggered my snake. however, now whenever i put my hand over his cage, he'll very quickly "stand" upwards, and put his head to the screen, almost as if he's going to strike my hand. i hadn't been able to handle him over the past one or two months, so maybe that could be the cause, but even so, he had always been very docile and gentle before. ive been scared to put my hand in cage, but i need to clean his cage. any idea why he's been behaving like this?