Scylla and Charybdis

Scylla was once a beautiful maiden, who was transformed into a hideous creature, with the heads of yapping dogs protruding from her midriff. Charybdis was a terrible whirlpool. Both these dangers were said to lurk in the Strait of Messina between Southern Italy and Sicily, a terror to sailors who endeavored to navigate these waters. The phrase between Scylla and Charybdis is much like the English between a rock and a hard place; it denotes a precarious position between two equally destructive dangers.