A cinematic underwater animation featuring a biomechanical octopus with glowing blue eyes and golden gears rotating around its tentacles. The creature floats gracefully in emerald-green water, surrounded by drifting bubbles and light rays filtering from the surface above. Its mechanical parts move rhythmically — gears turning, valves releasing air, and metal joints flexing as it slowly swims forward. The camera circles smoothly around it, capturing its movement in slow motion. Subtle particles, caustic lighting, and volumetric rays create an immersive, otherworldly atmosphere. Steampunk aesthetic, ultra-realistic textures, 4K cinematic quality.