The Owl Limpet is not an owl. It is a shell like critter that can get up to more than 7.5 cm (3 inch) and has a round low profile. It is usually black or brown with areas of white on it. The Owl Limpet sometimes has some patterns on its shell. This limpet has a large chestnut-brown area at the top in the inner surface of the shell that resembles the silhouette of a Great Horned Owl with its "ear" tufts extended strait out.
This limpet sits clamped shut on a rock all day and at night goes around exploring and munching on Ulva or similar seaweed.