Onnanoko

Onnanoko ("young girl," romanized from the Japanese 女の子) is a hidden opponent in the game Wrecking Crew '98, faced in Stage B, which is unlocked by defeating Gotchawrench within three minutes. When Mario enters the building, she teleports in front of him and says that she's been alone for a long time. She asks Mario if he can play with her, which he agrees, initiating the match. After her defeat, her true ghostly nature is shown; her transparent form is shown outside the crumbling building and, thanking Mario, she grows a pair of angelic wings and a halo and ascends into the sky. Defeating her also unlocks her as a playable character in VS. Mode and Tournament Mode. A girl very similar to her has been seen on promotional material for WarioWare Gold, including the box art, featuring the same name and a very similar appearance.