This article explores the connection between media fandom and intertextuality by looking at online fans who have moved between the movie franchise Twilight and one rock band featured on the soundtrack. Drawing on Matt Hills's work on “inter-fandom” and using fandom for the rock band Muse as a case study, this article first examines positive examples of inter-fan movement and the pleasures of discovering new fandoms. It also shows what happens when such movement is blocked-when attempts to move beyond Twilight fandom into band fandom are discursively policed by existing followers of the artist. Second, the article relates these practices to “anti-fandom” (Gray) to consider how anti-fan discourses and practices emerge. It offers an example of what I am terming “accidental anti-fandom,” where seemingly unrelated fan cultures are forced into opposition. Adopting the notion of the “interloping fan,” the article explores distinctions operated by Muse fans to prevent the “infiltration” of their fandom by “interloping fans” of the Twilight series. Given the cultural dismissal of young female fans in some existing work on both music fandom and Twilight, the article draws on theories of distinction to show how hierarchies based on gender, age, and knowledge continue to perform crucial functions within contemporary fan cultures.