This strange-looking crustacean is known as an arrow crab. Arrow crabs are quite common on the reefs of the Florida Keys and the Gulf of Mexico, where they scavenge for craps and dead fish. They get their name from the shape of their heads, which resemble an arrowhead. This arrow crab is scavenging for food in the tentacles of a sea anemone. The crab's hard shell protects it from the anemone's sting.