Today there was a book sale in the lobby of the building where I work. They also sell toys and novelties. I saw the salespeople demonstrating one of the toys and had to buy it for the cats (<$6). It's called a "Weazel ball." "The Playful Weasel Chases & Jumps the Rolling Motor Ball". (For ages 3 and up.) It's made in Taiwan. It has a rotating motor inside for locomotion (AA battery included).