The Japanese spider crab has the greatest leg span of any arthropod, reaching up to 5.5 m from claw to claw. The body may grow to a size of 40 cm in carapace width and the whole crab can weigh up to 19 kilograms, second only to the American lobster among all living arthropod species.
This crab was known to the Japanese for the serious injuries it can cause with its strong claws. The Japanese spider crab is occasionally collected for food, and even considered a delicacy in many parts of Japan and other areas in the region.
Information Courtesy: Wikipedia