Watercolours, pencil crayon and markers on watercolour paper. If a hydrus sees a crocodile sleeping with its mouth open, the hydrus will roll itself in mud(to become slippery), slide down the crocodile’s mouth and eat its innards. It will finally eat its way out through the belly, killing the crocodile. Mmmm.
For more info on all your favorite medieval beasts, visit The Medieval Bestiary or your local library.