Sandworms dig through tightly packed earth and stone, and they do it fast. They have acid pouches in their mouths, which allow them to digest rock while burrowing. That means they can make short work of flesh and most types of cloth. They usually kick up a dust cloud when they’re underground, making it possible to spot them, but finding them at night can be real hard. They’re common in the Plateau; less so in Northfields and Kaibab Forest.