A beloved Twilight vampire as an undercover cop? Or a baker for bachelor parties? Yep, welcome to "fan fiction," a trend that allows amateur writers to re-imagine famous characters and post works online, the Wall Street Journal reports. Not only is it popular—fanfiction.net is home to millions of works—but well-known writers like Meg Cabot and Cassandra Clare got their start in fan fiction. In fact, EL James' popular Fifty Shades series started as a sexed-up, sadomasochistic version of Twilight.
Some authors, like JK Rowling, support fan faction (hey, it's free marketing) but Anne Rice and Diana Gabaldon are among those who disagree. "They're stealing an audience they're not entitled to," says Gabaldon, author of the Outlander books. Most fan fiction, however, is free, not very good, and floating in a copyright gray zone. "A lot of people don't understand why I would devote time to this," says a 35-year-old sales manager whose stories riff on Twilight. "It's just fun." (Read more fan fiction stories.)