Lake Cocytus is the frozen lake of the ninth circle of Hell, within the circle is the center point of it, the highest peak of Hell is where Lucifer's Cage is located, where those who have committed treachery against God are punished. The lake itself is formed from the tears of Lucifer himself, and the flapping of his wings keep it frozen. It is here that Oracle fights Lucifer at the end of Season 5. In the middle of Lake Cocytus is a reversed pentacle that can show images and can be taken apart.