The Overlord is a villainous character seen in Gary Goodspeed's dreamworld in the episode "The Happy Place".
In Gary's personal dream, provided to him by the powers of The Happy Place, The Overlord is the leader of the Frost Bears. He is a feared villain that only Gary can stop. Gary first takes on the Overlords army, and defeats them with his dance moves, but the Overlord strikes back by kidnapping Gary's wife and children.
Gary thus personally confronts the Overlord at this throne to free his family. The two engage in a final dance battle, which Gary wins with the help of an army of antrophomorphic cookie-dancers. After being defeated, The Overlord explodes.