Like the brittle star the cushion star is not the common starfish, but closely related to it. The cushion star has much shorter arms and no spines, unlike the brittle star, why? The reason is because it lives in easier concealed spots. While the brittle star lives in open reefs the cushion star lives in grassy seaweed forests of the pacific and southern atlantic, making it difficult to spot for predators. It is one of the most abundant sea stars. It too can regenerate limbs and it can also crawl. However, it is much more powerful in how it latches on and how it feeds. It is almost impossible to pull the cushion sea star off of a rock, while the brittle sea star it is done much easier but difficult because of the spines on its back. Lastly, the cushion sea star feeds by a much larger, powerful beak that clamps down on mussels and clams to eat them. It is a more effective feeder than most other sea stars.