An octopus is a type of aquatic creature belonging to the cephalopod family, which includes SQUID, DEVILFISH, and molluscs. It is characterized by its eight arms and two eyes, and is found in many oceans around the world. SQUID are cephalopods with ten arms and two tentacles, while DEVILFISH are large, predatory cephalopods with eight arms and two long tentacles. Molluscs are soft-bodied invertebrates with a shell or mantle, and include snails, clams, and oysters.