The Watcher Heart is a small, intricate component harvested from the robotic Watcher creatures in Horizon Zero Dawn. It features a central core with a glowing blue energy source, surrounded by metallic plating with a slightly weathered and scratched surface, indicative of the machine's post-apocalyptic origins. The core emits a faint pulsating light, suggesting its importance as a power source, while the surrounding structure is angular and symmetrical, with precise mechanical detailing that reflects the advanced technology of the ancient world.