Every Filipino family knows someone who has been killed by the "bangungot." In Filipino folklore, bangungot is personified as a fat man who creeps into the bedroom of sleeping men and sits on their faces to suffocate them.
It isn't a fat man that kills them, but an unexplained illness that kills young, healthy Asian men and was first reported in the Philippines in 1917 and has since been identified in Thailand, Japan, India, and Singapore.
Known as Sudden Unexplained Nocturnal Death Syndrome (SUNDS) by medical researchers, the victims of the disease have been males in 99 percent of the cases, and 80 percent of those men were between the ages of 22 to 45. The death usually occurs during the first third of the sleep cycle and results from a miocardial infraction in the lower left ventricle of the heart, thereby causing a heart attack. The victims are found lying on their backs in bed, often with a frozen expression of what appears to be terror on their faces, thus giving rise to the folktale of the fat man having smothered them.
Chokroverty, Sudhansu, ed.; Robert B. Daroff, introduction. Sleep Disorders Medicine: Basic Science, Technical Considerations, and Clinical Aspects. Burlington, Mass.: Butterworth-Heinemann Medical, 1999.
Lyall, Kimina. "Stranglers in the Night." The Australian, May 2, 2002. [online] http://www.theaustralian.news.com.au/o,5942,4240606,00.html.
"Odd Syndrome Targets Asian Males." Wired News, April 2, 2002. [Online] http://www.wired.com/news/medtech/),1286,51473,00.html.