Machine Muscle is a fibrous, synthetic material harvested from the robotic creatures of Horizon Zero Dawn, resembling organic muscle tissue but with a metallic sheen and intricate circuitry patterns. It has a flexible yet durable structure, with a surface that alternates between smooth, biomechanical segments and rough, exposed wiring areas. The color palette ranges from deep reds and purples to silvery blues, with occasional glowing accents that hint at its energy-conducting properties.