That One Gun, known better as The One Gun, is an unknown weapon discovered in New Mexico ages before any attachments to it were made. Only one copy is in existence, and it chooses its owner by appearing at their feet. It can only be fired one time, where it reveals from one large bullet, an extending one. When shot, the recoil is so strong, it flies backwards into the hands of the next owner. The bullet can penetrate through anything, and only after 7 hours, will stop moving and disappear. If it hits anything organic, it will cause an explosion, and if that weighs over 250 lbs, causes a small nuclear explosion.