The Mighty Flea by YoYoFactory is a very small miniature metal yo-yo with a diameter of only twenty-five millimeters (or one inch), first released in December 2008. It is the smallest production yo-yo in the world. This special project yo-yo is made out of nickel-plated brass instead of aluminum, so that it could weigh closer to other modern yo-yos of the time of its release. It has a mascot in the form of a muscular, anthropomorphic flea in an old-timey weightlifting ensemble, complete with a barbell.