A closer look

Your body suddenly deciding to build a second skeleton inside you sounds like a Cronenberg horror film, but it's a real disorder. Fibrodysplasia ossificans progressiva (FOP) is a cruel glitch in the human genome that interprets minor muscle injuries as a cue to generate bone. Over time, any bruise or torn ligament permanently calcifies, slowly locking the victim into a rigid, living statue made of their own rogue skeletal tissue.