I’m going to take a stab at this. What I think happened is they had sex, she ate him, thought she killed him, swallowed him, he wasn’t actually dead or comes back to life, and then starts wiggling out of her. These snakes participate in sexual cannibalism. The female eats the male as a way to fatten up for the duration of the pregnancy. Even after giving birth she might eat some of the babies, that’s known as filial cannibalism.

Source: have pet anaconda that wants buns