Final answer:
Spider crabs use camouflage to help disguise them on the reef.
Step-by-step explanation:
Spider crabs, closely related to the Alaskan King Crab, use camouflage to help disguise them on the reef. They blend in with their environment, such as the sand or coral reefs, making it difficult for predators to spot them. Camouflage is an adaptation that many organisms use for protection and survival.