Octopuses and clams are both molluscs. Molluscs are a large phylum of invertebrate animals that include creatures such as snails, clams, octopuses, and squids. They share certain characteristics such as a soft body, a muscular foot for movement, and a mantle that secretes a shell in some species. While both octopuses and clams are molluscs, they differ in many other aspects. Octopuses are cephalopods, known for their intelligence and ability to change color, while clams are bivalves, known for their two-part hinged shells.