Just about any small worm, tiny clam or other animal it meets on the ocean floor. It has a tough shell, the color of mud, which also helps it hide. It also digs down into the ocean bottom and gets partly covered. Horseshoe crabs are slow and clumsy, but they have been on Earth for 200 million years while the dinosaurs have come and gone. They are called crabs but are really related to spiders and scorpions.
Sea stars live in the ocean.
Many have 5 arms and look like stars. Others have 40 arms. They look like sunflowers. Sea stars have a bumpy body covered with small spines. Hundreds of tube feet help them to hold on to things and to move around.