Fufu Bunny

The Fufu Bunny is a very rare Hard Mode passive monster which only is aggressive towards Field Mice. It does one damage to them and has 10 hp. If you catch a Fufu Bunny, you can give it to the Wizard. He will give give you 10 Gold Coins for it, along with a Goon.

Trivia:

This is a reference to the rhyme, Little Bunny Fufu.