This article presents a refined theory of paratextuality and bridges the gap between Kathryn Batchelor’s understanding of paratexts as a “consciously crafted threshold” and the risk of paratext’s “collapse into the vastness of ‘the context’” through a new form of paratextual relationship: collateral paratextuality. Doing so facilitates investigations into how audiences engage with complex constellations of paratextual materials in digital spaces, rather than analyzing paratexts in isolation. Such an approach is particularly relevant within translation studies given the proliferation of media content across linguistic and cultural borders within our increasingly networked and algorithmically mediated digital world. To demonstrate the utility of collateral paratextuality, this article concludes with a case study of the teaser trailer for Netflix’s Dark as hosted on YouTube, where the coalescence of content from different paratextual creators, YouTube’s mediation thereof, and the personalized nature of the platform both justifies and necessitates a collateral paratextual approach.