Spontaneus Human Combustion

Spontaneous human combustion (SHC) is the alleged burning of a person's body without a readily apparent, identifiable external source of ignition. The combustion may result in simple burns and blisters to the skin, smoking, or a complete incineration of the body. The latter is the form most often 'recognized' as SHC.

There is much speculation and controversy over SHC. It is not a proven natural occurrence, but many theories have attempted to explain SHC's existence and how it may occur. The two most common explanations offered to account for apparent SHC are the non-spontaneous "wick effect" fire, and the rare discharge called static flash fires. Although mathematically it can be shown that the human body contains enough energy stored in the form of fat and other tissues to consume it completely, in normal circumstances bodies will not sustain a flame on their own.

Read more on WIKIPEDIA