While postmodern metafiction (or reflexive fiction) is commonly positioned outside the scope of the Ontological Turn due to metafiction’s association with postmodernism’s insistence on “world as text,” this article argues that metafiction’s proximity to scientific theories of reflexivity engenders a shift toward what the article calls body as text, a shift that is synchronous with reflexivity’s evolution from cybernetics to biological autopoiesis. To trace metafiction’s aesthetic evolution from world as text to body as text, the article examines Jorge Luis Borges’s short story “The Circular Ruins” (1940) alongside early-order cybernetic theories of reflexivity before examining Salvador Plascencia’s The People of Paper (2005) alongside later theories of biological autopoiesis. While both narratives demonstrate an interest in the world-building powers of the text, the article argues that Plascencia’s novel demonstrates reflexivity’s autopoietic ability to examine the interstitial relationship between material embodiment and nonhuman agencies. By moving away from Borgesian self-regulation toward self-assembly, The People of Paper gradually sheds the epistemological preoccupations of its world-as-text aesthetic in favor a more ontological body-as-text aesthetic, thereby opening up the possibility of interpreting Plascencia’s novel as an aestheticization not of the construction of reality but of the construction of the body itself. In marking a distinction between world-as-text metafiction and body-as-text metafiction, the latter emerges as a uniquely useful heuristic in the Ontological Turn for modeling molecular embodiment and nonhuman agency.