New Delhi, April 14 -- A 32-year-old man in China walked into a hospital with what seemed like a routine complaint: stomach pain. There was nothing unusual at first glance. What doctors found next, however, turned the case into something almost unbelievable.

During a scan at the Longgang branch of The First Affiliated Hospital of Wenzhou Medical University, doctors noticed a strange object inside his body. It was lodged in the duodenum, the C-shaped section of the small intestine. The finding was shocking. It was a mercury thermometer, the South China Morning Post reported.

The man, identified by his surname Wang, then revealed a story he had hidden for two decades. At the age of 12, he had accidentally swallowed a thermometer.

Fear to...