The representation of autism in literature is a novelty of a delicate sense for what impact it can have on readers. Autism shows more frequently in the lines ofYoung-Adult fiction (YA), a genre known for its large audiences, which makes contemplating the image of an autistic person, as an actual character or a theme, either a means of access or a block to public awareness of the spectrum, respectively. The selected YA fiction works for this paper are Fantastic Beasts and Where to Find Them, as screenplay (2018) and book (2001). The screenplay is not an adaptation of the book, but a background to the times when a character wrote his study book on the beasts that surrounds his environment. In the works, the use of terms like “monster” and “beast” seems to refer to a dehumanised image of the represented, which raises questions on why the writer would allude readers to relate autism to monstrosity; is she maintaining the habit of using illness as a narrative thematic tool or does she suggest otherwise? In order to formulate a ground for these inquiries, we will visit the text in relation to Lacan and Derrida’s thoughts on “Subjectivity” and how it defines fellowship from alterity and monstrosity. The objective of this research is to investigate the representation of autism in Rowling’s screenplay while backing up with examples from the book to see how far it meets the real or contrastingly contributes to reinforcing another stereotypical other.