Grass Trekkers were semi-sentient predatory mammals native to the forest moon of Endor. They were aggressive and warlike, attacking any groups with whom they came in contact. On one occasion shortly before the Battle of Yavin, the Grass Trekkers attacked a group of Gupins who lived in a fortress. The Gupin Punt gave them the key to the Juniper Chest, which helped rejuvenate the Gupins' shapeshifting powers. The Gupins then asked for help from the Ewoks of Bright Tree Village, and together, they recaptured the key and drove the Grass Trekkers away.