Lub Glubs are enemies first seen in the episode "Beautopia." They are the main antagonists in the episode, and attempted to stop Finn, Jake and Susan Strong from relighting the City Heart of Beautopia, as their weakness is light. They resemble normal pool floaties, but once released, they take on a demonic appearance. There is one big one.
- They may have been formed when Beautopia's City Heart went out.
- When Susan draws the Lub Glubs on the boat, for no apparent reason Jake says that looks like his father. And also when grabbed by the large Lub Glubs, for no reason that reminds him of his mother.
- One of the Lub Glubs are seen chewing a skeletal head, which resembles Fionna's.