Virupa (Skt. Virūpa; Tib. བི་རུ་པ་, བི་ཝ་པ་, Wyl. bi ru pa or bir wa pa) was one of the eighty-four mahasiddhas of India and an important source of the teachings set down in the Lamdré of the Sakya school. He is also known by the name Tutop Wangchuk (Tib. མཐུ་སྟོབས་དབང་ཕྱུག་, Wyl. mthu stobs dbang phyug). Acting as the abbott of Nalanda university, he secretly practiced Tantra during night time and eventually encountered a vision of Nairatmya who provided him with sub-sequent empowerments. Due to his controversial tantric behavior after this event he left the university and took the name 'Virūpa' (ugly one).