There’s a rare disease whose victims appear to turn into stone. Fibrodysplasia ossificans progressiva is a condition where muscle tissue, tendons, and ligaments become replaced by bone.
The condition usually begins with the neck and shoulders and spreads to the rest of the body as it progresses. This results in a loss of mobility, sometimes even going so far as to prevent people from eating and breathing. It’s very rare, it occurs to only 1 in 2 million people worldwide.