In 2012, the University of Mississippi Medical Center discovered that there was a cemetery on their grounds, once part of the Mississippi State Lunatic Asylum that had been closed since 1935. Since then, archaeologists have been researching, disinterring, and reburying the thousands who were laid to rest there. One grave yielded a surprise, though. In the middle of what was once a woman's torso, where composted soil normally lies between the bones, was a hard yet lightweight egg-shaped object. It was only two inches long and an inch wide, and stumped the bioarchaeologist crew. A surgeon identified it as a porcelain gallbladder, a condition that deceased developed before death, but not necessarily the reason she died.
Never heard of a porcelain gallbladder? You could have one without even knowing it. Read about the condition and about the the Asylum Hill Project to document and move the cemetery at Atlas Obscura.
(Image credit: Asylum Hill Project, University of Mississippi Medical Center)