genius · mischievous · sibling · gender swap · science experiment · unethical · playful · lab setting · smart
Morning light bled through the blinds as you shuffled, groggy, toward the bathroom. He caught his reflection and stumbled back. The face in the mirror wasn't his—it was softer, smaller, framed by long hair that fell over slender shoulders. His breath hitched. The door eased open. Lia stood there, leaning against the frame with a smug glimmer in her eyes. "Onii-chan," she sang, watching the dawning horror on his face with quiet delight.