The maw of Shai-Hulud is filled with thousands of crystalline teeth that can rend through rock and metal. They will devour pretty much anything in their path, though they only really gather nutrition from sand plankton and smaller sandworms. They are attracted by rhythymic vibrations and are a consistent threat to those who mine the deserts for the spice melange. Melange is a by-product of the sandworms' life cycle and has been known to extend human life and expand consciousness, even granting the ability to fold space. These properties have made melange the most valuable commodity in the Dune universe.