Cinematic 8k wallpaper of a colossal Cthulhu towering near a vintage lighthouse perched on a moss-covered rock; the sea churns violently in a storm. The composition is centered with a sharp focus showcasing an atmosphere of megalophobia. An extremely detailed 4k digital painting captures a subtle, organic glow emanating from the creature, enhancing the photorealistic and cinematic movie quality. The scene is dark and moody, with dramatic lumen reflections and atmospheric lighting highlighting every intricate detail. Subsurface scattering and hyperrealism enhance the texture and depth, creating an insanely detailed, highly realistic photo reminiscent of 64k UHD quality. Modeled with the precision of a DSLR photograph, it leverages the power of Unreal Engine 5 and an Octane render for an unmatched 8k experience with slight atmospheric variations enhancing the mystique.