king crab is not a crab. Spider crabs have longer legs than king crabs, and they have two extra legs. King crab is a crustacean of Lithopodiaceae, not a real crab, mainly distributed in cold seas. Named after its huge size, it is known as the king of crabs. Because of its huge size and delicious meat, many species can be widely caught as food. Spider crab is a subfamily of crustaceans, with a full class of mollusca, which is a general term for invertebrates of Spider Crab Family. Spider crabs have a hard shell and the longest forelegs in crabs, so they are named after resembling spiders. Its body is thick and round, its feet are slender and its movements are slow. Most people eat carrion. Spider crabs have spiny carapace, sharp legs and long walking feet. Spiny spider crab is the largest crab in Europe, with nearly 1 different species along the coast of Australia. Although it has long claws and eight slender legs, it looks like a spider, but it is dull and easy to be caught.