The Leviathan is a monstrous autonomous vehicle that guards the undersea entrance to Atlantis in Atlantis: The Lost Empire. It served with neutrality, protecting the city from all who would approach it. In "Atlantis: The Lost Empire," Milo and the crew succeed in avoiding the beast and gain passage to the city. However, this is not done without a great many casualties and the destruction of their submarine. It is assumed that the Leviathan still guards the city, though now allows entry to those with permission from the Atlanteans.