What in the World offers you glimpses of what our journalists are observing around the globe. Let us know what you think: whatintheworld@nytimes.com

Which household gadget do people in South Korea believe can kill you?

(A) Microwave.

(B) Blender.

(C) Electric fan.

(D) Portable CD player.

The correct answer is C.

It sounds like the plot of an “X-Files” episode: People are said to have died merely from leaving their electric fans blowing overnight. But across South Korea, many people believe the whirring blades can cause death — and to address those fears, manufacturers equip fans with sleep timers.

How, exactly, might the electric breeze kill? Theories abound in South Korea, among them that the cold air circulating in a sealed room could cause hypothermia, leading to organ failure. Or maybe they suck out the oxygen, causing suffocation. Some fear that the fan itself converts oxygen molecules into carbon dioxide.