A cuero can flap about in the water within 10 feet of a riverbed or lake bed and stir up mud, pebbles, sand, silt, and other debris. This creates a hemispherical cloud in the nearby water with a radius of 30 feet (or to the edge of the water, whichever is closer). The cloud obscures all vision, including darkvision, beyond 5 feet. Creatures 5 feet away have concealment, while those farther away have total concealment. In non-flowing water, the muddy cloud dissipates in 2d6 rounds. In flowing water, the duration is reduced by 1 round for every 10 feet per round the water flows beyond 20 feet.