Some starfish can turn their stomach out onto their prey. This is how animals digest their food outside of their bodies. When the prey is pre-digested, the starfish pulls the stomach back inside with food pulp.
Instead of eyes, starfish have light-sensing cells at the ends of their five arms. With them they can perceive differences in light.
Contrary to what many people think, not every type of starfish has five arms: some have significantly more arms and others look more like a ball or a sea urchin.