Everywhere you look, the serial killer looks back at you. Streaming services finance endless documentaries about notorious killers, broadcast networks greenlight miniseries telling similar stories, podcasters jump in, social media debates ensue, amateur content proliferates – around the world. There seems to be an uncanny alliance between participatory digital media culture and the mythos of the serial killer. The serial killer, we argue, is not an accidental exemplar of contemporary digital culture—it is a totem upon which people can project their anxieties about dehumanisation uniquely experienced in a digital environment. For our argument, we consider what people – professionals and amateurs alike – do online with the serial killer as practices that function to (re-)appropriate existing serial killer discourse into a new media language that belongs to the Internet.