The Behemoth has let the cat out of the musty prison cell with details about Battleblock Theater's's trading system, which was inspired by the hacking of weapon drops in Castle Crashers. Battleblock Theater players will be able to collect the faces of other prisoners by freeing them with green gems found in co-op levels, and weapons by distracting their feline foes with balls of yarn. All weapons and strangers' faces for you to wear as your own will be randomized, and there are no duplicates of any one item, meaning trading will play an important role in collecting the pieces you want.

If you see an item -- let's say, a face -- on another player online, rip off your face and throw it at him, and if he returns the gesture, you've traded. Sounds painful simple enough. There are over 100 unlockable weapons and faces in Battleblock Theater, with more in the works before launch, which is scheduled for later this year. We recommend stocking up on lotion (or hoses) now.

This article was originally published on Joystiq.