Echidna was a half-woman, half-snake monster in Greek Mythology, who was known as the mother of all monsters, as she gave birth to most of the beasts referred to in Greek myth. In some tellings, she was the daughter of Tartarus and Gaia, while some other tales claim her to be the daughter of either Ceto and Phorcys, Chryasor and Callirhoe, or Peiras and Styx. She was known to have mothered Orthrus, Cerberus, the Hydra, the Chimera, the Gorgons, the Colchian Dragon, Scylla, and many more minor beasts. She was eventually killed in her sleep by Argus.