Squash
A small but quite amusing mod that uses the ArtemisLib library to give anvils a new ability - they can flatten entities. When an anvil falls on any mob or player, they immediately get squashed to a size twenty times smaller than normal.
The good news is that the compression effect is partially reversible. You just need to jump - with each jump there's a chance to return to your original appearance. A simple but very hilarious way to spice up the regular Minecraft gameplay.
A demo of the mod in action is available at the link:
