I have a male spider banana ball python. His name is Custard and I've owned him for a little over a year. I imagine he's only a year and a half, and around 2 feet, 7 inches in length. I have yet to weigh him, but he shows no signs of being overweight.

His temps are high 80s in his warm spot (with belly heater), and low 70s on his cold spot. The ambient humidity is usually high 50s to mid 60s in the winter, mid 60s to mid 70s in the summer. Both sides have adequate hiding spots and his tank is 30 gallons. I use aspen shavings as bedding too. He has had a couple stuck sheds, but they are always removed with a light soak.

He has always been a great pet and never refused a feeding, even during shed. At first, he had trouble with deciding where to start eating, but once he reached a couple months he was incredible at feeding. However, lately I've had a lot of trouble.

In the past couple weeks Custard has been doing weird things during feeding time. He will start off fine, but when he has most of the mouse down (with the tail sticking out), he starts twisting around. His neck will twist into strange positions as if he's choking and he'll turn red as if he can't breathe. I've even heard him squeak out in this position before. It's almost like it's involuntary.

Ive been using the same size mice (large) for a while now. I'm only now switching to two medium mice because he's getting bigger. I dont know why he would suddenly start doing these behaviors.

Thank you so much for reading. I'm really worried about my baby. I was thinking it could be his spider morph or possibly that he just doesn't like the mouse tail in his way.
Any suggestions are welcome. I want to try and help him so he doesn't hurt himself.