Backstrap cannon

This small cannon has straps similar to a backpack. It looks rusty and like it has been used in many altercations the craftsmanship looks very much like a goblin design and the small stature of the cannon might prove the origin of it.

Once strapped to your back you can begin properly using it. This can be used at disadvantage while standing or if you are prone you can use it normally. It can be used once per long rest and to use it you need a hunk of metal at least worth 1 gold and gunpowder worth 1 silver. It has a -1 to hit and does 3d4+6 bludgeoning damage and if the hit creature is medium or smaller they must make a strength check of 15 or be knocked prone.