SUNDS

Sudden unexplained nocturnal death syndrome (SUNDS) is a disorder found in southeast Asia, particularly Thailand, Japan, Philippines and Cambodia, which causes sudden cardiac death (usually in males) during sleep (1–3). This disorder, which is the most common cause of ‘natural’ death in the young, healthy Asian population, is called by many descriptive terms in the various countries, including pokkuri (‘sudden unexplained death at night’) in Japan, lai-tai (‘died during sleep’) in Thailand, and bangungut (‘moaning and dying during sleep’) in the Philippines.

- Human Molecular Genetics (read full article here)

Bizarre. The most common cause of "natural" death.