The Castle at the Edge of the World
This tiny tin wind up toy is made to look like a woodsman holding a tiny steel ax. When the key is wound in his back and he is set on the ground next to a tree of any size, he will proceed to chop away with his ax. The woodsman can fell a tree of any size in a single minute.
If used against a creature of the plant type the woodsman has a to hit of +10 and does 4d6 points of damage. The woodsman has an AC of 10 and 1 hp. It will attack for 10 rounds before its spring is wound down.
If wound more then once a day the mechanism will break and the woodsman will become non-magical.