While searching for food, a hungry cat finds a mouse who tells him where to find a tasty canary. However, the canary is scrawny because he's been sick, so the cat feeds the bird some "Jumbo Gro." After a little chasing, everyone is drinking the juice to grow big. Once the participants have taken a few swigs, suburban America, and then the world, are rampaged by four gargantuan domestic pets.