Between a rock and a hard place
Ulysses and his men have just recovered from their ordeal with the Sirens and are dreaming of the home-cooked food in Ithaca, but first they have to pass through Scylla and Charybdis, two mythical monsters that are the top dogs in the area.
Scylla has six heads to feed, so once in a while in between her regular diet of sea creatures, she snacks on a sailor or two that happen to be passing by. Charybdis sits on a rock opposite Scylla and sucks up the water three times a day, creating a whirlpool that not even Poseidon can survive.
According to Circe’s advice, Ulysses should avoid Charybdis, go close by Scylla to give her the cover charge and leg it out of there.
When they reach this treacherous area, the sea is choppy and Ulysses informs his companions to stay far away from the whirlpool, but doesn’t tell them about Scylla so they won’t feel like a tasty meze for the monster. And thus, as they are going past her cave, six heads pop out and snatch up one of Ulysses’ men. The rest row like they are competing in an Olympic final and manage to escape the monsters and continue their journey to Ithaca. Or at least, that’s what they think…