NUPPEPPO

This is one of the legendary creatures of Japan.  It looks like and smells like rotting flesh but it has vestiges of a face about it.  It seems to wander about at night in desolate places.  It has arms and hands.  It is able to move very quickly.

 If you eat its flesh, you should gain eternal youth.  I think you're more likely to get food poisoning, but it's an interesting piece of folklore, nonetheless.