Hornfels is a Cragnon that is green in color unlike most common Cragnons who are blue in color.
Hornfels is one of Flint Cragley's crew with the other being Monzo. Hornfels can be found in a room of Floro Caverns where the heroes must go and get him per Flint Cragley's orders. After getting Hornfels (and Monzo) back to Flint Cragley, Flint blames them for losing the key. However, it is revealed that Flint had the key in his pocket. Hornfels continues to follow Flint and Monzo around.