Cinematic 8k wallpaper featuring a gigantic Cthulhu towering near a lighthouse perched on a moss-covered rock. The scene showcases a stormy sea with waves crashing violently against the rugged coast. Cthulhu, rendered in sharp focus, displays intricate details and an organic glow, achieving photorealism with a dark and moody atmosphere. Light reflects off its scales, highlighting subsurface scattering and realistic textures. The atmospheric lighting enhances the scene's megalophobic nature, creating a hyperrealistic impression of grandeur. The 64k UHD digital painting is captured with DSLR clarity, utilizing Unreal Engine 5 and Octane Render techniques for an intensely detailed, movie-quality visual experience.