Sokushinbutsu- embalming process that begins before death

One of the more famous and recent examples is a buryat mummy of Dashi Dorzho Itigilov

His mummy is extra creepy because it has elastic skin, hair and fat so it looks as if he's still alive (see pic in the article):

According to Buryat Buddhists, Itigilov’s body is so well preserved because the Lama is still living, having achieved the higher meditative state known as śūnyatā, or emptiness