Thissermounts, creatures with short, stump-like legs, inhabited the desert planet of Jakku. These beings featured fragile hair manes and served as mounts for the anchorites residing there. Gallius Rax, an orphaned child, likened the look of the thissermounts' manes to the desiccated hair he observed on the many corpses scattered across Jakku's deserts.
The first mention of thissermounts occurred in the 2016 novel Aftermath: Life Debt, penned by the author Chuck Wendig.