A ghoul ghost is a ghost that guards its own body and refuses to leave. From ancient times to the present, in the world of ghosts, such beings have always existed. In the world of ghosts, they guard corpses. In his eyes, the white bones that looked at him were still him. When we look at his dead body, all that is left is a pile of bones, but to him, he still looks like himself. It's as if a heavenly being came to our human world and could walk on water because he saw that the water was glass. But we humans, beings in the Dharma Realm, see that water is liquid. Liquids sink to the bottom as soon as you drop them. However, devas saw that the water was glass, so they could walk on it. This is a natural phenomenon in the Dharma Realm space and is not dependent on human will.