In Greek mythology, Scylla and Charybdis were a pair of monsters who lived on opposite ends of the Strait of Messina between Italy and Sicily Scylla was originally a sea nymph who was loved by the sea god Poseidon*. Out of jealousy, Poseidon's wife Amphitrite poisoned the waters in which Scylla bathed. This turned Scylla into a six-headed beast with three rows of sharp teeth in each head. When ships passed close by her, she struck out to grab and eat unwary sailors.
Charybdis was also a sea nymph, as well as the daughter of Poseidon. Zeus* transformed her into a dangerous whirlpool across the strait from Scylla. Ships sailing the strait were almost certain to be destroyed by one of the monsters.
nymph minor goddess of nature, usually represented as young and beautiful
epic long poem about legendary or historical heroes, written in a grand style
In the Greek epic the Odyssey], the hero Odysseus lost his ship in Charybdis, but he managed to save himself by clinging to a tree overhanging the water. Later the whirlpool spat up the ship, and Odysseus dropped to safety on its deck. The legend of the two monsters gave birth to the phrase "between Scylla and Charybdis," meaning a situation in which one has to choose between two equally unattractive options.
* See Names and Places at the end of this volume for further information.