What's worse than a pile of dead babies?
One at the bottom that's still alive.
What's worse than that?
It's forced to eat its way out.
What's even worse than that?
It comes back for seconds.
This is a dark and disturbing joke that escalates in horror. It starts with a horrible image of dead babies and gets worse with a live baby in the mix, then adds the imagery of the baby eating its way out and returning for more, creating a very morbid punchline.