BASILISK, n. The cockatrice. A sort of serpent hatched from the egg of a cock. The basilisk had a bad eye, and its glance was fatal. Many infidels deny this creature's existence, but Semprello Aurator saw and handled one that had been blinded by lightning as a punishment for having fatally gazed on a lady of rank whom Jupiter loved. Juno afterward restored the reptile's sight and hid it in a cave. Nothing is so well attested by the ancients as the existence of the basilisk, but the cocks have stopped laying.
2009 update: A swift-footed iguana maladapted for metaphor.