An octopus is a soft-bodied sea creature with eight long arms covered in suction cups. Each arm can move independently, allowing the octopus to explore rocky crevices, manipulate objects, and catch prey like crabs and small fish. The name comes from Greek words meaning “eight feet.”

Octopuses are among the most intelligent invertebrates on Earth. They can solve puzzles, open jars, squeeze through impossibly small spaces (their only hard part is a tiny beak), and even learn by watching other octopuses. Most remarkably, they can change both their color and texture in seconds to blend perfectly with coral, rocks, or sand. This camouflage helps them hide from predators and sneak up on prey.

When threatened, an octopus might spray dark ink to create a confusing cloud while it escapes. Some species can also detach an arm to distract a predator, then regrow it later.

Scientists have discovered that octopuses have neurons throughout their arms, meaning each arm can almost “think” on its own while the central brain handles bigger decisions. This distributed intelligence helps explain how they can do eight different things at once.

The plural can be either octopuses or octopi, though octopuses is more common and technically more correct.