The literary hoax is a process and/or a final product challenging the place, the function, as well as the credibility of an author. Often reduced to mere trickery, deceit or imposture, the literary hoax is in fact a concept that showcases different manifestations of double or multi-authorship, for it implies, in most cases, a fictitious authorial figure. This multiplicity of authorship creates a mobility that has seldom been analysed. This article proposes to identify the movements of the authorial function within three different types of literary hoax, in order to problematize and explore the notion of authorial mobility. The problematization of the concept of the author within this particular framework will enable us to shed new light on authorship itself, but also on the authors – fictitious or not – at the heart of this multiplicity of authorship. Through the examples of Vernon Sullivan, Émile Ajar and other plagiarists, this article will demonstrate that fictitious authors can indeed gain authorship.