Once an ordinary mountain creature, the Sheepsquatch underwent a profound transformation after centuries of dwelling in caves permeated by the Thunderbird's energy filtered through layers of earth. As it consumed minerals infused with this power and slept within crystalline chambers, its flesh and wool gradually merged with the surrounding sandstone, allowing it to access the geological memories and ancestral wisdom embedded in the rock strata of the Great Plains.

The Sandstone Sheepsquatch can phase its body partially or completely into sedimentary rock, moving through solid stone as if navigating through different layers of time and memory. It perceives vibrations through the earth with extraordinary sensitivity, detecting hidden chambers, water sources, and ancient artifacts buried deep within the Great Plains' geological formations. When threatened, it can harden its woolly coat into impenetrable sandstone armor or crumble parts of its body into sand to escape through narrow crevices before reforming elsewhere.

As the living embodiment of the land's geological memory, the Sandstone Sheepsquatch guides the Earthbound Guardians to artifacts and wisdom preserved in specific rock layers, each corresponding to different eras of the Thunderbird's influence on the Great Plains. It serves as both translator and guardian of these stratified histories, ensuring that only those with proper reverence for the earth's secrets can access the power and knowledge contained within.