(sandworm, Maker) Sandworm of Arrakis, the "Old Man of the Desert," "Old Father Eternity," and "Grandfather of the Desert." Significantly, this name, when referred to it in certain tone or written with capital letters, designates the earth deity of Fremen hearth superstitions. Sandworms grow to enormous size (specimens longer than 400 meters have been seen in the deep desert) and live to great age unless slain by one of their fellows or drowned in water, which is poisonous to them. Most of the sand on Arrakis is credited to sandworm actions. (See Little Maker.)

Shai-Hulud is the Fremen term for the sandworm of Arrakis.

As with many Fremen terms and words, Shai-Hulud is more than a mere descriptive term for a physical entity. Specifically, it often alludes to the Fremen belief that the sandworm is a physical embodiment of the One God that created and governs the universe. Thus to the Fremen Shai-Hulud is a sacred term that is usually spoken with a tone of awe, fear or respect.