A cephalopod is a marine mollusk belonging to the class Cephalopoda, which includes animals like octopuses, squids, cuttlefish, and nautiluses. Characterized by their bilateral symmetry, complex nervous systems, and ability to change color and texture, cephalopods are known for their intelligence and advanced behaviors. They typically have tentacles equipped with suckers, and most are capable of rapid movement and jet propulsion. Cephalopods are also notable for their unique reproductive strategies and complex life cycles.