It sounds like something out of a horror film or TV show, and it is, but spontaneous human combustion (SHC) is also a very real possibility, and it has been used to explain many deaths over the years.
For those not familiar with this bizarre occurrence, SHC refers to "the burning of a living (or very recently deceased) human body without an apparent external source of ignition." Basically someone bursting into flames for no apparent reason. Sometimes the entire body is reduced to ashes, while other times some limbs remain completely intact. One thing is for sure, with only 200 cases in the last 300 years, the phenomenon is rare, and survivors even more so.
What causes it?
Investigators have struggled to come to a conclusion about how SHC occurs. Some believe that rare natural phenomena are the cause, while others believe it to be factors such as the victims unknowingly having cigarettes lit in their pockets, or alcoholism as a 1938 British journal theorized.
Another theory, suggested in 1961, was that SHC is the result of the 'wick effect' in which a persons clothing acts as a wick like you have on a candle, and the body fat acts as a long-burning fuel source, eventually reducing a body to ash, but this theory doesn't account for how the body actually ignites.
However, In 2012, Professor Brian J Ford had somewhat of a break through on the subject and now seeks to disprove these theories, believing something else is at play. After many experiments Professor Ford thinks that higher-than-normal levels of acetone, which the body produces naturally (unlike alcohol) could be the reason behind SHC. Ford wrote in his study that "a range of conditions can produce ketosis, in which acetone is formed, including alcoholism, fat-free dieting, diabetes and even teething." Could he be on the way to proving that SHC is real?
Recently documented victims
One of the latest documented cases was a 3-month-old boy named Rahul, from India. In 2013, according to his parents Rahul had spontaneously caught fire on four different occasions, the first time when he was just nine days old.
While this may may sound farfetched, it gets stranger. Just one month ago, Rahul's mother brought her second baby to the hospital with burns on his feet, claiming he had spontaneously combusted. A team continues to investigate this second occurrence, though no signs of abuse were found when her elder son, Rahul was brought to hospital two years ago.
In 2011, the death of an Irish man in Galway, Ireland was ruled by the coroner as death by spontaneous combustion, the first of its kind in Ireland. 76-year-old Michael Faherty (no relation to me as far as I can tell!), was found lying face down near an open fire, though forensic experts found that the fire had not been the cause of the fire. The fire which killed the 76-year-old was confined to the living room, and only the area directly above and below the body in the room was burned. Curiously Mr Faherty had Type 2 Diabetes, which could have seen his body produce acetone, backing up Professor Ford's theory that SHC is very real.