佛教认为毕舍遮是饿鬼道众生之一，有学者认为薛荔多鬼和饿鬼的名称都由它衍生而来。 《大毗婆沙论》认为毗舍遮拥有畜生外相故属于畜生道。 毕舍遮是四大天王持国天王的部属。在藏传佛教密宗理论中，毕舍遮位于现图胎藏曼荼罗外院之南，形如饿鬼，手持人的残肢、或“劫波罗”（Kapala，髑髅）。
Pishachas (Sanskrit: पिशाच, Piśāca) are flesh-eating demons in Hindu theology. Theology describes them as the sons of either Krodha (figuratively “Anger”) or as Dakṣa’s daughter Piśāca. They have been described to bulging veins and protruding, red eyes. They are believed to have their own languages, known as Paiśāci.
According to one legend, they are sons of Kashyapa and Krodhavasa, one of the daughters of Prajapati Daksha. The Nilamat Puran of the 7th century mentions the valley of Kashmir is inhabited by two tribes: the Nagas and the Pisachas.
Piśācas like darkness and traditionally are depicted as haunting cremation grounds along with other monsters like bhutas and vetālas. Piśācas have the power to assume different forms at will, and may also become invisible. They feed on human energies. Sometimes, they possess human beings and alter their thoughts, and the victims are afflicted with a variety of maladies and abnormalities like insanity. Certain mantras are supposed to cure such afflicted persons and drive away from the Piśāca which may be possessing that particular human being. In order to keep the Piśāca away, they are given their share of offerings during certain religious functions and festivals.
The origin of Piśāca is unknown, although it may be the personification of the will-o’-the-wisp. Pāṇini, in his Aṣṭādhyāyi, described the Piśāca as a “warrior clan”. In the Mahābhārata, the “Piśāca people” (equivalent to the modern day Pashtun people) are said to live in barbaric parts of Hindu Afghanistan and they are descendants of Prajāpati Kaśyapa.