Scylla and Charybdis

These two creatures gaurd the pass that leads into the Sea of Monsters.The phrase "between Scylla and Charybdis" (or between a rock and a hard place) has come to mean being in a state where one is between two dangers and moving away from one will cause you to be in danger from the other. Scylla was a grotesque sea monster, with six long necks equipped with grisly heads, each of which contained three rows of sharp teeth. Her body consisted of twelve canine legs and a cat's tail. She was one of the children of Phorcys and either Hecate, Crataeis, Lamia or Ceto (where Scylla would also be known as one of the Phorcydes). Some sources, including Stesichorus cite her parents as Triton and Lamia

Scylla
Scylla was a beautiful water nymph once but a goddess or enchantress changed her into a monster with six heads for she broke the heart of a man. She picks off sailors from ships and eats them.(NOTICE: this monster killed Amilia Airheart)

Charybdis
Across from Scylla Charybdis is located. Charybdis makes whirlpools. If you go through the Bermuda Triangle (a.k.a. the Sea of Monsters) you have to choose between Scylla or Charybdis. You can also go through the Clashing Rocks if you prefer to get