The Preta realm is the domain of Hungry Ghosts — beings tormented by insatiable craving. Depicted with vast, distended bellies and needle-thin throats, they can never consume enough to fill their emptiness. They represent the intense state of craving, greed and addiction which are usually the reasons that one can be reborn in the preta realm.
As a result of intense greed, jealousy, miserliness and attachment to things in their previous lives, they will be reborn as a hungry ghost. As a consequence, they experience insatiable hunger for repugnant things such as feces or corpses. In addition to this, they are also known to experience disturbing illusions, such as seeing water as pus or food as feces.
Pretas are invisible to the human eye, but some believe they can be discerned by humans in certain mental states. They are described as human-like, but with sunken, mummified skin, narrow limbs, enormously distended bellies and long, thin necks. They also suffer from immoderate heat and cold — the sun causing them to feel freezing temperatures.
Pretas are considered a little more than nuisances to humans. They exist in the same physical world as us, but only humans of lower spiritual disposition can see them with the naked eye. In some traditions, they are considered to have some sort of power that they can use to prevent humans from satisfying their needs out of jealousy, either through illusions or by frightening them.
Generally, they are considered as beings to be pitied, and there are festivals that commemorate them or alleviate their suffering, albeit only for a short period of time.