This bearded fireworm (Hermodice carunculata) must have a strong stomach -- it’s sucking on fire coral (Millepora sp.), which would give the unlucky snorkeler a nasty sting. Encountered in St. John, U.S. Virgin Islands, the worm in this photo is about 15 cm (6 inches) long, but they can get up to twice that length. Those venom-filled bristles can break off in human skin, causing an intense burning sensation. More about coral reef species can be found in the Coral Reefs section.