Leeches are aquatic worms known for their diet of blood. Most leeches feed by lurking in murky water and biting onto larger animals that haplessly wander too close. The leech hangs onto its prey using circular jaws, slowly drinking the animal's blood over many minutes, often without the prey even noticing.

Some leeches can grow to giant proportions, up to three or four feet long and almost one foot wide. These giant leeches will hunt any prey that is larger than them. Each one can drain an entire human body's worth of blood in a single meal, swelling to almost twice its original size and turning a ruddy crimson after gorging. Some claim that these leeches were created long ago through magic or divine intervention, while others believe that they are just a naturally-existing variety of leech.

Giant Spitting Leeches. Some rare populations of giant leeches are capable of spitting their digestive juices at nearby enemies, used either to ward off predators when threatened or, when they are swarming as a group, to weaken dangerous prey before going in for a bite.