Lulu (stereotypically called the Mysterious Girl) is a self-proclaimed Luxeville's hero and Wario's arch-enemy in WarioWare Gold. Her name is revealed in Wario's final stage (Wario Deluxe) in WarioWare Gold when she introduces herself after his defeat.
Lulu was aware that Wario stole the potty. In Crystal Park, Lulu practiced confronting to Wario, but she was distracted with the rainbow. Meanwhile, Lulu was eating. A small dog, Ruffington approached her. She allowed him to eat her food and they slept. After Lulu woke up, she realized that she got carried away.
Wario Deluxe encouraged the player to give up. However, Lulu assisted the player. Defeating Wario Deluxe, Lulu demanded him to give the pot; but Wario refuses. Lulu squirted water with the Hydrocannon LX at Wario. After Wario transformed back to himself, Lulu stated the object was a potty. Convinced Wario returned it.
Lulu and Ruffington returned to Luxeville with the potty. The elder tells Lulu that they recently installed a modern toilet which Lulu faints.