Create a hyper-realistic depiction of Gengar as if imagined by Stephen King. Picture a dark, rotund, levitating form with oily, purple skin, giving an unsettling, almost grotesque aura. Its blazing red eyes gleam with malevolence, and its wide, jagged smile exudes malicious intent, like a grin from someone unseen whispering your name in the dark. Shadows around Gengar move with an eerie sentience, stretching towards the viewer like skeletal hands, and a ghostly, echoing chuckle lingers in the background. It thrives on fear, always a step behind, feeding off every nervous glance.