, also known as Park Eun-suh and Samara Morgan, is the main antagonist of Koji Suzuki's "Ring" novel series and the film franchise of the same name. Sadako's fictional history alternates between continuities, but all depict her as the vengeful ghost of a psychic who was murdered and thrown into a well. As a ghost, she uses nensha, her most distinctive power and weapon, to create a cursed video tape that will kill whoever watches it exactly one week later unless the tape is copied and shown to another person, who then must repeat the same process.