During the course of the Captain Scarlett DLC, you'll encounter Sand Worms multiple times. This is likely a reference, even if indirectly, to a creature from the 1965 Sci-fi classic Dune by Frank Herbert called a Sandworm.
The book takes place on a planet that was likely once covered in oceans but have long since dried up. Much of the planet has been almost covered of sand punctuated with large wave like dunes. The Sandworms are known for tunneling under the surface of the sand. Unlike their classic brethren, the sandworms of Borderlands will, in fact, eat you.