The Fraggles are a race of childlike mutant creatures who live underground alongside a race of tiny gnomes called Doozers. The Doozers, who look like stubby construction workers in little utility belts and hardhats, do nothing but work, because it is in their nature. The Fraggles, who do nothing but play, live primarily by tearing apart and devouring the "radish dust constructions" the Doozers build. When a Fraggle wants to eat, he tears off a chunk of "radish dust" scaffolding, carelessly flinging six or seven hapless doozer workers to the ground in the process.
In the land of Fraggle Rock, Doozers may not associate with Fraggles. Those who do are punished.
Here's a blurb from the back of a Fraggle Rock video I picked up today, the episode entitled "Doozer Doings:"
"Cotterpin Doozer is two days away from getting her helmet and becoming a full-fledged doozer worker. Except she doesn't want to be a doozer, she wants to be a Fraggle, because Fraggles do all the things that Doozers don't--they play! But she discovers it is not that easy to try to be something that you are not."
In the following episode, "The Preachifying of Convincing John," a nice fraggle tries to convince her friends that it's mean to eat the Doozers' radish dust buildings. By the end of the episode we learn that one shouldn't meddle with the natural order of things because, you see, the Doozers _need_ the Fraggles to eat their radish dust constructions or they'd run out of things to do.