Rōba (ローバ) is a female character in the One Piece seventh movie and is also the main antagonist Ratchet's mother. She was found by the Straw Hat Pirates at the beginning of the movie closed in a chest. Monkey D. Luffy and his crew accept to bring her back home, in Karakuri Island, with the promise to have in return a legendary treasure hidden on the island. Despite being Ratchet's mother, she doesn't approve her son's plans to control the giant turtle and conquer the world, and often, during the movie, she tries to make him change his mind, with the only effect of being imprisoned in the castle's dungeon with the Straw Hats. In the end, after Ratchet was defeated, she spanked him.

(source: onepiece.wikia)