The Alligator Snapping Turtle
When wondering what something out of a Hieronymus Bosch painting would look like in the real world you need look no further than the Alligator Snapping Turtle.
The one below appears to have a jungle of moss growing on its back. It's easy to imagine these creatures as giants with vast landscapes stretched across their shells.
To see more pictures of this strange beast visit the photo gallery on flickr.