XIII is the fourth studio album by American heavy metal band Mushroomhead, released on October 14, 2003. The album reached No. 40 on the Billboard 200. By 2006, it had sold 177,000 copies in the United States and 400,000 copies worldwide, making it the band's most successful album to date. It is the second Mushroomhead album to be distributed through a major label, and it was also the debut release for then-new guitarists Bronson and Gravy, as well as turntablist/sampler Stitch.