The film involves a group of misfit monsters (Susan, also known as Ginormica, a woman who was hit by a giant meteorite on her wedding day and grew to be 50 feet tall, B.O.B, an indestructible gelatinous mass-created when a dessert topping was combined with a tomato, Dr. Cockroach, a scientist who became a bug man after his experiment went wrong, the Missing Link, a 20,000-year-old macho fish man who was thawed out by Arctic explorers, and Insectosaurus, a 350-foot tall grub after being mutated by nuclear radiation) hired by the United States Armed Forces to stop an alien invasion and save the day in exchange for freedom.
