Shimmering, miragelike, a tree of steel thorns appeared out of the haze and a sudden dust storm of ochre sand. The thing seemed to fill the valley, rising at least two hundred meters to the height of the cliffs. Branches shifted, dissolved, and reformed like elements of a poorly tuned hologram. Sunlight danced on five-meter-long thorns. Corpses of Ouster men and women, all naked, were impaled on at least a score of these thorns. Other branches held other bodies. Not all were human.