A sinister supernatural entity depicted in the style of a detailed bestiary illu

A sinister supernatural entity depicted in the style of a detailed bestiary illustration. It has a semi-skeletal face with almost no human features, featuring hollow eye sockets that emit an ominous light. Twisted horns curl from its forehead, and its body is surrounded by a black, sand-like aura that swirls menacingly. The entity is cloaked in dark, ethereal robes that blend seamlessly with the shadows. Its overall appearance is otherworldly and unsettling, with an aura of dark mysticism. The illustration should emphasize its arcane and malevolent nature, showcasing the creature with intricate details typical of bestiary art, capturing its ancient and fearsome presence. Bestiary simple sketch, antique art, in bestiary book.