A starfish is a marine animal with a distinctive star-shaped body, usually featuring five arms radiating from a central disk. Despite their name, starfish aren't fish at all: they're echinoderms, a group that also includes sea urchins and sand dollars. Scientists often call them sea stars to avoid confusion.

Starfish have remarkable abilities that seem almost magical. If a predator bites off one of their arms, they can slowly grow it back over several months. Some species can even regenerate their entire body from a single severed arm. They move using hundreds of tiny tube feet on their undersides, creeping slowly across the ocean floor. When hunting, a starfish can push its stomach out of its mouth and digest prey like clams and oysters right inside their shells.

You'll find starfish in oceans worldwide, from shallow tide pools to the deep sea. They come in vibrant colors: purple, orange, red, blue, and pink. While they look harmless and many people enjoy spotting them in tide pools, some species have venomous spines. If you ever encounter a starfish at the beach, it's best to observe without touching, since taking them out of the water can harm them.