The human body is an amazing machine, but when things go wrong it can be a real mess. Most of these messes are understood by the medical community after decades of research and study. But some simply defy explanation. From diseases that accelerate aging to diseases that stop aging, ones that cause your muscle to turn to bone and ones that make filaments grow out of your skin, to allergic reactions to water and deadly cannibal conditions, here are some of the weirdest.