Japanese mystical ascetics mummified themselves alive by eating a strict diet of poisonous pine needles

A closer look

The Sokushinbutsu took the concept of a detox diet to a horrific extreme. To achieve ultimate mystical enlightenment, these monks spent years eating only tree bark, pine needles, and a toxic sap used to make lacquer. The goal was to eliminate all body fat and literally embalm themselves from the inside out while still breathing. If they succeeded, they became revered holy relics. If they failed, they just died terribly in a box.