Have you ever wondered, what is a sea biscuit shell? A sea biscuit shell is the external skeleton of a marine creature known as a sea biscuit, which belongs to the echinoderm family, closely related to sand dollars and sea urchins. These shells are distinctive for their rounded, dome-like shape and the intricate star patterns on their surface. Unlike the flat sand dollar, sea biscuit shells have a more three-dimensional form, which helps protect the creature inside as it moves along the ocean floor, feeding on detritus and organic matter. Knowing what a sea biscuit shell is can enrich your beachcombing experiences, as you’ll be able to identify these unique shells and appreciate their role in the marine ecosystem. These shells are not just beautiful collectibles; they are also a testament to the incredible diversity and adaptability of life in our oceans.