This thesis examines, recontextualises, and provides a new methodology for analysing a collection of Internet phenomena known as ‘Creepypasta’. Critically engaging with its form and participation in the Gothic and horror literary traditions, I argue that creepypasta should be considered as an emergent genre that manifests through the form of digital fiction and derives a renewed horror and Gothic affect through that form. Existing as unnerving tales written for and spread across social media and Web2.0 websites, creepypasta is an acknowledged, but under-studied genre of fiction. The majority of scholarly attention has analysed creepypasta through the lens of folklore studies which, while aware of the affordances of its digital form, considers creepypasta as folklore first rather than being attentive to media specificity or situating its form and unnerving affective qualities at the centre of its definition. I attest that creepypasta is emblematic of fourth-generation digital fiction and a continuation of horror and Gothic literary traits. In particular, I forward that creepypasta leverages its form to reinvent and renew ways of engaging with the Gothic traits of threats and ontological ambiguity. This, I argue, is primarily achieved through what I define as “ontological flattening”, whereby real users and their responses, and the fictional story they are reading and responding to exist in the same textual space without borders, implied hierarchy, or explicit indicators of fictionality in the story text. Throughout my analyses of Candle Cove (2009), The Slender Man (2009), and The Interface Series (2016), I demonstrate how ontological flattening is central to how creepypasta renews Gothic characteristics. In chapter 4, I forward a development on Isabelle Klaiber’s “double plot model” of collaborative interactive fiction to take into account collaboration in ontologically flattened spaces. In chapter 5, I also introduce the concept of the techno-Weird as a new form of contemporary Gothic fiction that uses ontologically flattened spaces as a way to emphasise characteristics of weird fiction. I conclude by presenting my model of the relationship between readers, creepypasta, and ontologically flattened spaces, and indicating where future applications may lie.