A variation of waterbending in which a master waterbender utilizes the power of the full moon to control the water in the blood of all living things. Hama, a survivor of the Fire Nation raids on the Southern Water Tribe, developed the technique while being held prisoner in a Fire Nation cell. The prisoners were given no water, so Hama had to improvise. She spent years developing the technique and practiced on the rats that scurried across her cage. Finally, she used her new skill to break out, controlling the guard to use his key to open her cage.