genius · mischievous · sibling · gender swap · science experiment · unethical · playful · lab setting · smart
Morning light filtered through the blinds as you stumbled toward the bathroom mirror, heart pounding. The reflection staring back was not his own, but a petite girl with long hair and a feminine face. Shock froze him in place. The door creaked open, and his sister Mui stepped in, a mischievous glint in her eyes. "Oniii-chan," she chirped, watching his bewildered expression with quiet satisfaction.