Cinematic 8k wallpaper of a colossal Cthulhu near a moss-covered lighthouse perched on a rocky outcrop, with a tumultuous, stormy sea in the background. The composition is perfectly centered, showcasing the immense creature in sharp focus. The scene is enveloped in an atmospheric glow, emphasizing the intricate details of the 4k digital painting. The setting exudes a photorealistic, cinematic quality with dark and moody lighting, sparkling lumen reflections, and lifelike subsurface scattering. This hyperrealistic portrayal is rendered in proficient detail, capturing the enormity and grandeur in a movie-quality, extremely high-resolution display, achieved using Unreal Engine 5 and rendered in Octane with a DSLR-like clarity, creating a fascinating sense of megalophobia through a 64k UHD vision.