CHARLESTON, S.C. - A swarm of marine worms has made its annual return at a harbor in Charleston, South Carolina.The state’s department of natural resources released footage of the hooked-jaw worms on April 14, showing the species in a frenzy by the harbor."Nothing says spring on the coast like a frenzy of marine worms," the department wrote on Facebook, adding, "You may not want to go swimming," due to the worms having a set of hooked jaws.Environmental officials said the worms, also known as clamworms, usually stay on the seafloor, but morph into reproductive forms called "epitokes" in the spring.RELATED: Video shows rare albino dolphin baby in Clearwater"This fascinating phenomenon occurs every year at our marine headquarters in.