Piggymitts, the baby pig. It follows you around and hits mobs, like a wolf. But it's a pig.
Remember to change the "insertnamehere" for the name of Piggymitts's owner.
You can change the animal type and name too.
HOW TO DISABLE:
Get into Creative mode and swing at its top until its name shows.
Then, it'll just be a normal, invincible baby pig that you can kill. (or not)