Sandworms are large, fictional creatures found in the science fiction universe of Dune, a novel by Frank Herbert. They inhabit the desert planet of Arrakis and can grow to be hundreds of meters long. Sandworms are essential to the ecosystem of Arrakis, as they produce the valuable substance known as spice, which is crucial for space travel and has various other properties. These creatures are known for their ability to sense vibrations in the sand, which helps them locate prey. Sandworms are also revered by the native people of Arrakis, the Fremen, who have a deep cultural connection to them and use them for transportation across the desert.