Typhon is the most monstrous being in Greek myth, the ultimate challenge to the rule of the Olympians. Born of Gaia (Earth) and Tartarus (the abyss), in some accounts specifically to avenge the Titans and Giants whom Zeus had already defeated, he is a creature of cosmic scale: so tall his head brushed the stars, his arms reaching from the eastern to the western edge of the world, with a hundred serpent-heads, eyes flashing fire, and voices of every kind. His assault on Olympus is the gods' gravest crisis; in some versions the Olympians flee in terror to Egypt, disguising themselves as animals, before Zeus returns to face him. Their battle convulses the whole cosmos, the sea boils, the earth quakes, until Zeus overcomes him with the thunderbolt and buries him beneath Mount Etna, whose eruptions are Typhon's fiery breath still escaping. He is also, with the viper Echidna, the parent of many of the great monsters the heroes must later face, the Hydra, Cerberus, the Chimera, the Sphinx. Typhon represents the final, largest surge of primordial chaos against the divine order, and his defeat and imprisonment complete and confirm Zeus's sovereignty over the cosmos.