One day in the land of Equestria, a young unicorn would gain a cutie mark unlike any other, and with it came a powerful new ability. Using their magic, they could transform other ponies into diapers to wear around their rear, and gain the strength, skills, and abilities of the transformed victim! Those transformed were still alive and conscious, but unable to move or speak, and the transformation could be temporary, reversable, or permanent, depending on the user's wishes. Needless to say, they intended to have a little of fun with their new power...