Modifies the skin to perform supplementary gas exchange — absorbing oxygen and releasing carbon dioxide directly through the skin surface, similar to frog and salamander cutaneous respiration. The modification cannot replace lung breathing in air (the oxygen concentration is insufficient for full metabolic support through skin alone), but it provides a critical 15–20% oxygen supplement that reduces breathing demands during exertion and can sustain basic consciousness for 10–15 minutes if lung breathing is obstructed. The skin must remain moist for cutaneous respiration to function — dry skin cannot perform gas exchange. Users develop an unconscious behavior of seeking humid environments and moisturizing frequently. Combined with the gill modification, skin respiration creates a triple-redundancy breathing system (lungs, gills, skin) that makes the user extraordinarily difficult to asphyxiate.