This mod adds a simple item, aswell as some others!
This item allows you to throw a Trapper at any entity in the world to capture them. (Yes, any entity.)
Entities captured will remain hostile (if so) and attack you. The trapper also works on modded entities.
TO USE:
First, you must craft a trapper. After it's crafted you will get a Grey disc shaped object, rmb to throw. Hitting an entity will instantly drop the entity inside the trapper to pick up, you can throw this again for it to drop the empty trapper and release the entity wherever it was thrown.