The sandworms — called Shai-Hulud among the Fremen of the desert planet Arrakis (Dune) — are worshiped as manifestations of "the earth deity of Fremen hearth superstitions." The Fremen believe that the actions of the sandworms are the direct actions of God, and so the worms have been given numerous titles such as the "Great Maker". Virtually indestructible and with indefinite lifespans of potentially thousands of years, they are cylindrical creatures with no significant appendages, equipped with a fearsome array of crystalline teeth, used primarily for rasping rocks and sand but more than capable of eating anything imaginable. Sandworms grow to hundreds of meters in length, with specimens observed over 400 meters long and 40 meters in diameter. These gigantic worms burrow deep in the ground and travel swiftly; most of the sand on Arrakis is credited to sandworm action. Sandworms are described as incredibly tough, atomics are the only explosive powerful enough to kill an entire worm, with conventional explosives being unfeasible as each ring segment has a life of its own. Water is poisonous to the worms, but is in too short supply on Arrakis to be of use against any but the smallest of them.