The fydern is a green creature roughly the size of a human fingernail. It has twelve short legs and two wiggling antennae, which it uses to catch microscopic bugs. Its body is covered in a thick, greasy layer of skin and fat. If a fydern is taken out of water, its legs will fold in, its antennae will become rigid, and it will quickly become a rock and die. Solid fydern are sometimes polished and sold as gemstones to those who don't know better, as they don't begin to stink until months after dying.