An octopus is a mollusk belonging to the class Cephalopoda, which also includes squids, cuttlefish, and nautiluses. Characterized by their eight flexible arms lined with sensitive suckers, octopuses are known for their intelligence, problem-solving abilities, and unique defense mechanisms, such as camouflage and ink expulsion. They inhabit various marine environments, from shallow coastal waters to deep ocean floors. Octopuses are also highly adaptable hunters, preying on crustaceans, fish, and other small marine animals. Their remarkable biology and behaviors continue to fascinate scientists and ocean enthusiasts alike.