Proteus the Monster was a son of Uranus in Greek mythology, and the being whose magic kept Atlantis shrouded in mist and unseeable to outsiders. He detained the Atlantean princess Ismene on his island under orders from her mother Queen Antinea, who intended to sacrifice her to prevent Atlantis' fall. However, the Greek hero Heracles chanced upon his island while searching for the lost King Androcles of Thebes, and Heracles slew Proteus when he transformed into a monster to prevent Heracles from rescuing Ismene. Heracles' slaying of Proteus removed Atlantis' protective layer of mist and enabled Heracles to bring Ismene back to Atlantis, setting the stage for Atlantis' downfall.