A Fremen device used to attract sandworms, consisting of a spiceplastic stake pointed at one end and attached to a spring-driven clapper at the other. Credited to Naib Trekam of Sietch Alraab, the thumper was adapted from an obsolete geological impact hammer after a survey team's encounter with a sandworm revealed that rhythmic low-frequency vibrations attracted the creatures. The thumper served two purposes: summoning a worm for riding, and decoying a worm away from a Fremen using a timed fuse. It was a standard component of every Fremkit.