On a jungle beach near the border between Panama and Costa Rica in 1996, Benjamin Radford found this strange animal that had obviously washed up. It was headless and mostly hairless except for a patch on its chest; it had four limbs, what seemed to be a stubby tail, and large claws at the end of each arm. The legs were spindly compared to the arms. Monster? A close inspection of the bizarre creature's paws revealed a clue. The three white claws were long and distinctive. Radford realized the monster had once been a regular sloth, turned into a monster by decay and predation. Credit: Benjamin Radford