Wormrider refers to those who mastered the skill of calling, climbing, and riding a Sandworm of Arrakis. The name referred also to the followers of the original wormrider, Selim Wormrider. They were the precursors of the Fremen. The Wormriders were Buddislamics who revered Shai-Hulud as a manifestation of Buddallah. They shared Selim's vision and ideals and were tasked to disrupt the commercialization of Spice. There were few non Fremen wormriders. Most notably Gurney Halleck who rode worms while in service of Lady Jessica.