I've had this 1 1/2 - 2 year old california king snake for about two months now, and up until Tuesday (4 days ago) he was the sweetest little thing ever, handled very well, was eating well, and had shed twice without issue. Tuesday I took him out of his cage to put him in the separate box I have for feeding (he'd regurgitated his previous meal a few days before) and he bit me out of the blue; not a quick or aggressive strike, he just kinda rested his head on my hand and decided to bite and didn't let go for a good ten minutes. After I got him to let go he ate his mouse like usual and allowed me to put him back in his cage afterwards. This was the first time he'd ever done anything even remotely aggressive so I didn't think anything of it. Today I saw he regurgitated his meal again (at this point it was just a little blob the size of an M&M so I'm not sure what to think of that) so when I moved him to clean it up he got all defensive and looked like he was going to try and bite me again. I let him slither out of the way of his own accord and when I touched him again he did the same thing, and was rattling his tail.
I checked the temp in his cage and it's normal, so I don't think that's the cause. At first I thought maybe my other animals might be bothering him; I have a leopard gecko who is absolutely enthralled with him, but my blue tongue skink and two cats don't show him any interest as far as I know so I think that's out.
I'm not all that experienced with snakes (and I'm very much a worry wart when it comes to my animals) so I'm not sure if this is the start of something bad or just a little tantrum of some sort. Advice?
