The creature is a Horseshoe Crab, although it is not really a crab. They are amazing creatures, and they are very important in the world of medicine. The chitin from their shells is used in the manufacture of absorbable sutures and special wound dressings for burn victims. The chitin reduces healing time by 35-50%. Their blood (which is blue), contains clotting factors that are used to test IV drugs and vaccines for bacterial contamination. They are not killed for their blood. Instead, they are caught, serve as blood donors, and are then released. Great care is taken to be sure that they survive to keep the population going.