No this is not the krusty crab this is Patrick.
Answer:
By keeping a thin skeleton, the sand dollar can camouflage itself in the sand.
Explanation:
Sand dollar are very small and peculiar sea urchins. They have very few predators like some fish and starfish, but they manage to get rid of predation with their own bodies, which is very useful for such a small creature. This is because sand dollars have small spines on their bodies, which in addition to allowing them to move forward on the ocean floor with great speed, allows them to hide in the sand, preventing their predators from finding them.
