Scylla was said to be a creature who was rooted to one spot in the ocean, and regularly ate sailors who passed by too closely. Her appearance has varied in classical literature; she was described by Homer in The Odyssey as having six heads perched on long necks along with twelve feet, while in Ovid's Metamorphoses, she was depicted as having the upper body of a nymph, with her midriff composed of dogs' heads. Charybdis was depicted with a single gaping mouth that sucked in huge quantities of water and belched them out three times a day, creating whirlpools.
According to myth, Odysseus was forced to choose which monster to confront while passing through the strait; he opted to pass by Scylla and lose only a few sailors, rather than risk the loss of his entire ship into the whirlpool. Jason and the Argonauts were able to navigate through without incident due to Hera's assistance, while Aeneas was able to bypass the deadly strait altogether.