Fireworm takes on fire coral. This bearded fireworm (Hermodice carunculata) must have a strong stomach! It’s sucking on some fire coral (Millepora sp.) that would give the unlucky snorkeler a nasty sting. Encountered in St. John, US Virgin Islands, the worm in this photo, is about 15 cm (6 inches) long, but they can get up to twice that length. Those bristles can break off in human skin, also causing a burning sensation.