Sokushinbutsu is a pretty far out method...
Buddhism in the extreme! In an obvious game of one-upmanship, a couple of dozen Japanese Buddhist priests have won the self-denial award by successfully mummifying themselves. The process takes years, but begins with the monk taking part in a diet and exercise regimen to burn away all body fat. Then they slowly poison themselves to induce vomiting and diarrhea to empty the body of bodily fluids. Then, the monk crawls into a box and remains in the lotus position until death, when the box is sealed. When the container of horror is reopened, you get a perfectly mummified Buddhist priest- in theory. Many, many people have tried to mummify themselves unsuccessfully. The practice is now outlawed in modern Japan, and thankfully no Buddhist sect advocates Sokushinbutsu.
