Gyūki (牛鬼), also called Ushi-oni (lit. "ox ogre") is the name for a variety of creatures from Japanese folklore, all some sort of monster with a bovine head. The most common version found in the series is one with the face of a cow and the body of a spider. According to legend, he disguises himself as a human and when he reveals his true appearance, it is even more dreadful than his reputation would imply. Some stories also claim that Gyūki disguises himself as a woman to lure in unsuspecting travelers.