Poison Emitter

Overview
The poison emitter is expensive to make at first as it requires dragon's breath, but free to use and can be recycled. Every 40 seconds, the poison emitter creates a cloud of poisonous gas which brings most mobs down to 1 health. Mobs such as zombies and skeletons are not affected by this, so it cannot entirely replace standard grinders.

Using the Poison Emitter
Throw the poison emitter item on a piston (facing up) to start the machine. Pistons facing up within one block of this will be flipped upside down. It is impossible to place to poison emitters adjacent to each other. You can break the piston at any time to get the poison emitter back.

Every 40 seconds, the poison emitter will create a cloud of poisonous gas which lasts for 5 seconds and gives Poison II to all affected mobs.

Update Notes
Version 0.1:
 * Added crafting recipe
 * Added functionality