Cinematic 8k wallpaper, colossal Cthulhu in stunning 4k, 8k resolution, dominant centered composition near an ancient lighthouse perched on a moss-covered cliff, turbulent stormy sea, extraordinary sharp focus, invoking megalophobia through incredibly detailed 4k digital painting, soft organic luminescent glow, photorealistic with cinematic and movie-quality elements, dark and moody ambiance, mesmerizing light reflections on the water, atmospheric lighting effects, subtle subsurface scattering for depth, hyperrealism achieved through intricate details, lifelike textures in 64k UHD, captured with a DSLR-like precision, employing Unreal Engine 5 and Octane Render for ultimate realism in 8k, slightly eerie yet awe-inspiring, epic scale with a foreboding presence amidst dynamic ocean waves.