The Fridge Monster is the beast that attacks the Bebop's crew in Session #11, "Toys in the Attic".
The Fridge Monster appears as a small black blob that slides around on the floors, walls and ceilings. It travels very quickly and can alter its shape as it moves. It can incapacitate a living creature by biting it, although it is unknown if the bite is fatal or not. The monster itself is a mutated Ganymede Rock Lobster - although what caused its mutation is unknown. The Fridge Monster is apparently edible with no adverse side effects as Ed eats the monster at the end of the episode.