This chapter explores how combining fan- and surveillance studies offers tools to examine vigilant, sometimes toxic practices that fans engage in. It does so by examining different practices of how fandoms hijacked narratives surrounding the Harry Potter-spin off series Fantastic Beasts and Where to Find Them (2016–current). Drawing on content analyses of online materials about the franchise and the different controversies it instigated, this study reveals four different practices of how fans hijacked the narratives surrounding the franchise: First, it is highlighted how fans denounced the involvement of actor Johnny Depp and campaigned to get him removed from the franchise. Second, the fandom called out producer David Yates and author J. K. Rowling for not taking a stand against Depp’s involvement. Third, following Rowling’s lack of countering Depp’s inclusion, fans continued to hijack the franchise narrative by shaming the author. Fourth, this chapter exposes how these escalated situations surrounding the franchise also challenged the norms and values of the fandom. The chapter explores how digital vigilantism is empirically present in the fandom, by mapping the different online practices fans engaged in to hijack the narratives surrounding their favourite franchise – through applying an innovative, interdisciplinary lens, and surveillance studies. By critically examining fans’ practices on a micro-level, this chapter might offer a point of departure or inspiration to also understand these challenges on a macro- or societal level.