The following link details a story in which the Yogi (Sree Sree Siva Prabhakara Sidhayogi Parama Hamsa) converted a human being to the Yeti in Himalayas with a special mushroom, a medicine belonging to a rarely available species. It is called 'Lingshi' in Chinese and 'Reishi' in Japanese.

Sree Sree Siva Prabhakara Sidhayogi Parama Hamsa known as Prabhakara Sidhayogi or Bhagavan (God) was the Guru of Matha Amrithanadamayi

http://members.tripod.com/siddhar/snow_main.htm

http://news.bbc.co.uk/1/hi/world/asia-pacific/3175926.stm

http://www.ammachi.org

A point to ponder !!