guests, or significantly abridged. Many versions of the chod sādhana still exist. Chöd, like all tantric systems, has outer, inner and secret aspects. They are described in an evocation sung to Nyama Paldabum by Milarepa: Vajrayogini is a key figure in the advanced practice of chöd, where she appears in her Kālikā () or Vajravārāhī () forms. The practices of Tröma Nagmo "Extremely Wrathful Black Mother" associated with the Dakini Tröma Nagmo (the black form of Vajrayogini) were also propagated by Machig Labdrön. One of the forms of this style of chöd can be found in the Dudjom Tersar lineage. Chöd is now a staple of the advanced sādhana of Tibetan Buddhism. It is practiced worldwide following dissemination by the Tibetan diaspora. Indian antecedents A form of chöd was practiced in India by Buddhist mahāsiddhas prior to the 10th century. The two practices of chöd in Buddhism and in Bön are distinct lineages. There are two main chöd traditions within Buddhism, the "Mother" and "Father" lineages. Dampa Sangye is known as the "Father of Chöd" and Machig Labdrön, founder of the Mahamudra chöd lineages, as the "Mother of Chöd". Bön traces the origin of chöd to the Secret Mother Tantra, the seventh of the Nine Vehicles of Bön practice. There are four distinct styles of chöd practice. Chöd developed outside the monastic system. It was subsequently adopted by the monastic lineages. As an internalization of an outer ritual, chöd involves a form of self-sacrifice: the practitioner visualizes their own body as the offering at a ganachakra. These two qualities are represented iconographically by the victory banner and the ritual knife. The banner symbolizes overcoming obstacles and the knife symbolizes cutting through the ego. The practitioner may cultivate imaginary fearful or painful situations since they help the practitioner's work of cutting through attachment to the self. Machig Labdrön said, "To consider adversity as a friend is the instruction of Chöd". Practitioners as 'mad saints' Sarat Chandra Das, writing at the turn of the 20th century, equated the chöd practitioner () with the Indian avadhūta, or "mad saint". Avadhūtas, called nyönpa in Tibetan Buddhism, are renowned for expressing their spiritual understanding through "crazy wisdom" inexplicable to ordinary people. Chöd practitioners are a particularly respected type of mad saint, feared and/or held in awe due to their roles as denizens of the charnel ground. According to tibetologist Jérôme Édou, chod practitioners were often