The creature in Greek mythology known for its ability to turn people to stone upon sight is Medusa. Medusa, one of the three Gorgon sisters, was cursed by Athena, transforming her beautiful hair into venomous snakes. Anyone who looked directly at her would turn to stone, making her a symbol of both fear and allure. Her defeat by Perseus and the use of her severed head as a weapon signifies the themes of transformation and the complexities of female power in Greek mythology.