Please describe the new feature or change.
Zombies can be trapped in a 2-block tall hole which ruins the added difficulty. If zombies are in a pit that is 2 blocks tall, they should be able to pull themselves out.

Please describe why you want this feature.
Players have been cheesing the zombies by digging a hole and jumping out with the wall-jump mod. There should be some way to counteract this. I want players to SUFFER THROUGH THE HORDE!!