Echidna

Echidna (Έχιδνα in Ancient Greek, meaning "she-viper") is the daughter of Phorkys and Ceto and is considered the mother of all monsters. Typhon is her husband.

History
Echidna was described by Hesiod as a female monster spawned in a cave, who mothered with her mate Typhon almost every major horrible monster in the Greek myths. Echidna was usually considered an offspring of Tartarus and Gaea, 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). Echidna was a dracaenae, with the face and torso of a beautiful woman (depicted as winged in archaic vase-paintings) and the body of a serpent, sometimes having two serpent's tails. She is also sometimes described as 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: thus chthonic Echidnae are presented as protectors of the vineyard.

The site of her cave Homer calls "Arima, couch of Typhon." 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, the hundred-eyed giant.

The Lightning Thief
While Percy, Annabeth, and Grover are at the top of the arch they encounter Echidna who also has the Chimera with her(The Chimera is in the form of a chihuahua). She quickly isolates Percy from his friends while he is waiting for a second empty elevator, and pits him against her monstrous son at the top of the arch. Percy barely manages to escape after being poisoned by the Chimera's snake tail and plummeting into the water below. She also seems greatly offended that the animal echidna (a spiny anteater from Australia) was named after her, and became even more furious when Percy brought it up.

Appearance
In the book Echidna is described through the Mist as an extremely fat woman with a fearsome chihuahua that is the Chimera. The only clues that she was a monster were her reptilian tongue, the fact that she called her dog "Sonny" and the fact that she has slit eyes like a snake. She apparently wears a lot of denim clothing to cover up her scaly skin (or maybe it is just covered in scales). According to Apollodorus, Echidna was a drakaina with the face and torso of a beautiful woman (sometimes winged) and the body of a serpent, sometimes having two serpent tails. It was known that she was cursed into time cycles, so she was a young girl in the morning a Maiden in the afternoon, and an old lady at night.

Children

 * Chimera
 * Hydra
 * Cerberus
 * Orthrus
 * Ethon
 * Crommyonian sow
 * Colchian Dragon
 * Drakon
 * Erymanthian boar
 * Ladon (some accounts)
 * Sybaris (possibly)
 * Manticore(possibly)
 * Scylla(some accounts)

Grandchildren

 * Sphinx
 * Hellhounds
 * Nemean lion
 * Gorgons