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. However, due to Spike previously setting the auto-pilot to land on Mars, she most likely succumbed to the monster's poison as well.