This study traces a Gothic realism in the dark, sensorial epistemologies emerging from intersections of documentary and horror cinema. From the ineffable subjects of horror documentaries and pseudo-documentaries, to the obsessive chroniclers of mockumentary, fake found-footage, and screenlife horror cinema, the films examined here express a generalized millennial and 21st-century archival anxiety around an unsettled and unsettling hypermediated reality. Part I focuses on gothumentaries, nonfiction works evoking the Gothic unreadable subjects and undetected realities. Case studies show key documentary films such as Capturing the Friedmans, Cropsey, and The Hellstrom Chronicle bring Gothic-horror tropes and conventions to bear upon documentary subject matter to produce skepticism of American environmental, social, and national stability from the 1970s onward. Part II explores mockumentary, fake found-footage, and screenlife horror cinema that turns to strategies of documentary and factual discourse to express an archival anxiety around human interaction with recording technologies. Case studies of pivotal films such as The Blair Witch Project, Diary of the Dead, Lake Mungo, Unfriended, Host, We Are All Going to the World's Fair, and The Outwaters trace Gothic realism as a key way of expressing the subject's relationship to, and experience of, a modernity that overwhelms in terms of its immensity, speed, and recordability. These fiction and nonfiction moving-image manifestations of Gothic realism adopt the mood, themes, and rhetorical strategies of horror and documentary to form a critical discourse that troubles the real--focusing spectatorial attention on the limits of representation and teleological forms, shifting viewers to questions of embodiment and sensation. The primary focus is on Anglophone cinema from the United States, the United Kingdom, and Australia, with reference to other works produced in Spain, Germany, and France.