The correct answer is Fibrodysplasia ossificans progressiva (FOP), sometimes referred to as Stone Man Syndrome,which is an extremely rare disease of the connective tissue. A mutation of the body's repair mechanism causes fibrous tissue (including muscle, tendon, and ligament) to be ossified when damaged. In many cases, injuries can cause joints to become permanently frozen in place. Surgical removal of the extra bone growths has been shown to cause the body to "repair" the affected area with more bone.
