the goddess fierce Echidna who is half a nymph with glancing eyes and fair cheeks, and half again a huge snake, terrible smelling, with greasy skin, eating raw flesh beneath the secret parts of the holy earth. And there she has a cave deep down under a hollow rock far from the deathless gods and mortal men. There, then, did the gods appoint her a glorious house to dwell in: and she keeps guard in Arima beneath the earth, grim Echidna, a nymph who dies not nor grows old all her days. —— (Theogony, 295-305)Usually considered offspring of Tartarus and Gaia, or of Ceto and Phorcys (according to Hesiod) or of Chrysaor and the naiad Callirhoe, or Peiras and Styx (according to Pausanias, who did not know who Peiras was aside from her father), her face and torso of a beautiful woman was depicted as winged in archaic vase-paintings, but always with the body of a serpent (see also Lamia). She is also sometimes described as having two serpent's tails. Karl Kerenyi noted an archaic vase-painting with a pair of echidnas performing sacred rites in a vineyard, while on the opposite side of the vessel, goats were attacking the vines (Kerenyi 1951, p 51f): chthonic Echidna as protector of the vineyard perhaps.
The site of her cave, Arima, Homer calls "the couch of Typhoeus" (Iliad, II.783). When she and her mate attacked the Olympians, Zeus beat them back and punished Typhon by sealing him under Mount Etna. However, Zeus allowed Echidna and her children to live as a challenge to future heroes. She was an immortal and ageless nymph to Hesiod (Theogony above), but was killed where she slept by Argus Panoptes, the hundred-eyed giant.
The offspring of Typhon and Echidna were:
Some sources also include the Gorgons and the Graeae as her children. Hesiod claims that Sphinx and the Nemean Lion were her children by her son, Orthrus. It is also believed that the eagle (some say vulture) that ate Prometheus' liver was also born to Echidna, though this has never been proven.