Several marine organisms, including sponges, corals,and algae, synthesize organohalides (halogen-containing organic compounds) that they use to deter predators. For example,red algae synthesize a toxic,foultasting organohalide that keeps predators from eating them. One predator, however, that is not deterred is a mollusk called a sea hare. After consuming red algae,a sea hare converts the original organohalide into a structurally similar compound it uses for its own defense. Unlike other mollusks, a sea hare does not have a shell. Its method of defense is to surround itself with a slimy material that contains the organohalide, thereby protecting itself from carnivorous fish.