I have a Rosy Boa. I suddenly heard a noise and looked at the aquarium, and the snake was holding on, by his mouth, to the black rim at the top of the aquarium. He was twisting his body and i could see his face moving, almost like when he's swallowing a pinkie. After a moment he fell. I decided to feed him a pinkie, because it's actually past due, and he grabbed the pinkie and threw it. Then he just ignored it but lunged upwards a few times, and once at me.

Any ideas?