This character is a ghost.

In traditional belief, a ghost is the soul or spirit of a deceased person or animal that can appear, in visible form or other manifestation, to the living. Descriptions of the apparition of ghosts vary widely: The mode of manifestation can range from an invisible presence to translucent or wispy shapes, to realistic, life-like visions. The deliberate attempt to contact the spirit of a deceased person is known as necromancy, or in spiritism as a séance.