Wizard rock is a genre of music generated by the fan culture surrounding the "Harry Potter" books. Since J.K. Rowling and the books themselves are so universally popular, many fans look closer to home to find new ways to channel their love for the series. Wizard rock songs are all about things that happen in the Harry Potter universe. As a genre, it has gone through many different incarnations, and its uniting theme is the content, not sound or quality. Though wizard rock fills a very specific niche, the fandom is big enough that it has a huge cult following and fan base of its own. There have also been spin-off bands playing music about "Doctor Who," "Lost" and the "Hunger Games." Only a handful of bands actually get known for their music, but famous wizard rockers have between several hundred thousand and over a million subscribers on YouTube and other forms of social media.