Shelby (AKA Showby) is a character in The Mr. Peabody & Sherman Show who appeared as the main antagonist of Biggest Fan / Queen Isabella. She is Mr. Peabody and Sherman's biggest fan. She has some of their merchandise, made a macaroni picture of them, and even wrote a book of ideas for the show (one of which being Sherman kissing her, which he hastily declined). She accidentally gets sucked into the Orcoptitron and started controlling the show and refused to stop unless Mr. Peabody and Sherman met her demands. At the end of the episode, Shelby decided to stop wrecking havoc if Sherman kissed her on the lips, which Sherman reluctantly did just as she got out of the machine. She also has a little sister named Lucy who is Mr. Peabody's biggest fan.