Echidna was a half-woman, half-snake mother of many monstrous progeny, including Ladon (a dragon), the Hydra, the Chimera, Orthus (a multi-headed dog) and Cerberus (the multi-headed dog that guards the gates to Erebus). Echidna and Orthus had their own foul brood, including the Greek Sphinx and Nemean Lion. Orthus was guarding the cattle of Geryon when he was strangled by Heracles.