Lub Glubs are creatures who appear in "Beautopia." They resemble glowing black globs with teeth and live inside of inflatable pool toys. The Lub Glubs appeared in Beautopia from somewhere unknown, driving out the Hyooman tribe who were too afraid to fight them. It is likely that the toys themselves were originally from the beautopia resort, as the lub glubs emerged from a tunnel marked "Floaty".
Lub Glubs are destroyed by bright light, and possibly chose to hide inside pool toys to avoid any trace light from their subterranean environment. Pool toys shown containing lub glubs include ducks, a dolphin, a snake, a pony, and an octopus. This behavior doubles as a disguise, as there is no evidence of the lub glub's shadowy form once it has fully sealed itself inside the toy. Lub glubs are carnivorous, as one can be seen gnawing on a skull wearing a rabbit hat.
They remained passive until Jake, trying to convince the terrified Susan Strong that they were harmless, tried to pop one with his "pickaxe hand." They spilled and burst from their floaties in hideous pitch-black forms, grappling the heroes with spindly arms. The Lub Glubs then take their true form—amorphous pitch-black masses showing only what appear to be teeth. Though stunned by regular attacks, their only weakness seems to be light; aware of this they tried to stop Jake from lighting the massive torch known as the City Heart, and when he did they burned away leaving no trace but the torn floaty toys they were hiding in.
Jake states twice that they remind him of his parents. First, a crude outline drawing of Susan reminded him of his father, which made him declare himself crazy. When confronted by a massive and especially horrifying Lub Glub, he claimed it reminded him a lot of his mother.
- The Lub Glubs' teeth looks similar to the Evil Monster in "Dad's Dungeon."
- A Lub Glub can be seen chewing on a Fionna-like skull.
- Lub Glubs could possibly be a creature affected by The Mushroom Bomb. This is because they share rather similar traits to Oozers