I appreciated Nicolson’s summing up the twin terrors as two aspects of the female threat.
‘After the monstrous-beautiful Sirens, Odysseus comes to the limb-consuming Scylla and her friend the body-gulping Charybdis. Scylla is a six-headed, rock-bound, man-eating monster, with guts made of dogs’ heads, who plucks you from above; Charybdis is a vast-mouthed, in-sucking, whirl-water hell-fiend who will pull you down below. Veer too far from Scylla, and Charybdis will have you. Too far from Charybdis, and Scylla will pick off your sailors. To far in or too far out, which fate will you choose? Together they are the nightmare of female threat, either picking your life away or drowning you in who they are.’
Source: Adam Nicolson, The Mighty Dead (London: William Collins, 2015), p. 240