Cinematic 8k wallpaper of a massive Cthulhu, towering in a centered composition near a weathered lighthouse perched on a moss-covered rock, the sea beneath is tumultuous and stormy. This scene features sharp focus with an unsettling sense of megalophobia, showcasing an extremely detailed 4k digital painting. The Cthulhu emits a faint organic glow amidst a photorealistic and cinematic setting, creating a moody atmosphere with enhanced lumen reflections and atmospheric lighting. There is a masterful use of subsurface scattering to portray hyperrealism, making the textures insanely detailed and lifelike. Captured as if by a high-quality DSLR using Unreal Engine 5 and Octane Render, the image exhibits 8k resolution, bringing every detail into stark, breathtaking clarity.