When veterinarians found half-foot-long worms living in their feline patients, they had discovered something new: The worms, Dracunculus insignis, had never before been seen in cats. The worms can grow to almost a foot long and must emerge from its host to lay eggs that hatch into larvae. It forms a blister-like protrusion in an extremity, such as a leg, from which it slowly emerges over the course of days to deposit its young into the water.