Quack in the Box is a fast-food restaurant owned by Quacky the Duck, that only appeared in Quack in the Box. Quacky tricked Dudley into destroying Argh-By's and Taco Bull, in order to make Quack in the Box the most popular restaurant in Petropolis. In the end, his plan backfired, and he was sent back to prison.
- The name of the restaurant is a parody of the fast-food chain Jack in the Box.
- It is known to serve really unhealthy, excessively greasy food.