Wiktionary
prep.phr. (context idiomatic English) A perilous journey between two dangers, similar in meaning to between a rock and a hard place
Wikipedia
Being between Scylla and Charybdis is an idiom deriving from Greek mythology, meaning "having to take a narrow path between two bad choices on either side". It differs from similar idioms, such as "on the horns of a dilemma", " between the devil and the deep blue sea", and " between a rock and a hard place" because in these expression there is no good option, whereas with "between Scylla and Charybdis" there is a possible path to success, although it is a difficult one.
Usage examples of "between scylla and charybdis".
Somehow they were between Scylla and Charybdis, on board Odysseus' vessel.
She would think of herself as a ship navigating between Scylla and Charybdis.
These reflect the narrow gate of hell, the choice between Scylla and Charybdis.
So now, my dear lord, you have the tyrant at your mercy, tossed between Scylla and Charybdis.
First, I know as well as you do that you're between Scylla and Charybdis —.