As I was farming Act II in Nightmare mode with my Demon Hunter, I was suddenly engulfed by a big rock worm, not only was it an elite boss, but it also had a lot of baby rockworm minions to accompany it. When I went back and looked closely at its name … it was Shaitan, The Broodmother … also known as the Great Maker!
On killing this elite, you get access to its random dungeon which spawns from where the worm appears. More loot and sadly no more references to dune. It would have been great if a dying fremen or two would have been there in that cave.