The earth-soul isn't the essence of the person but a sort of crude copy or mimic. It may become a hungry ghost and prey upon the living. Most ghost phenomena, these researchers note, are repetitious and purposeless, more like video or audio recordings. Ghosts, according to the belief, can manifest to any and all the senses. A ghost may present itself as an image, sounds, odors, tactile, feelings of cold, a feeling of intruding presence, or any combination of impressions.
Some parapsychologists consider ghosts and poltergeists separate phenomena.
In this case the viewer experiences what amounts to an hallucination, but its ultimate source is outside him. Animals, with senses more acute than man's, are supposed to be able to see or sense the presence of ghosts, even if humans on the scene sense nothing unusual. Folklorists generally distinguish two types of mythical ghost, the spectre-ghost or apparition, frightening but harmless, and the hungry ghost, which actively preys upon the living. Vampires are a form of the hungry ghost. Even today in the industrialized world, belief in ghosts and hauntings, or at least allowing their possibility, is widespread and held by many people, including the educated.