One day Douma has ate too many donuts. He looked down at his rear and noticed a shocking sight. He had a big fat ass! He jiggled it around amazed and then Muzan caught an eye on him. And he LOVED IT. He told him to jiggle it more or else he would die. So he jiggled it more and more until Muzan was pleased. He then one day when encountering the Insect Hashira, Shinobu he realized he had gained a new blood demon art.. MEGA FART.