Virupa (Sanskrit: Virūpa; Tib. bi ru pa or bir wa pa,lit. 'ugly one'), also known as Virupaksa and Tutop Wangchuk, was an 8th-9th century Indian mahasiddha and yogi, and the source of important cycles of teachings in Tibetan Buddhism. He is especially known as the source of the Lamdré ("path-fruit", Skt. mārga-phala) system held by the Sakya school and is thus seen as the Indian founder of their lineage. A series of verses called the Vajra verses, which are pith instructions on the Hevajra tantra, are also attributed to him.