Augustine's repeated returns to Genesis allow him to revisit and readdress vexing topics. One of these is the question of the animal. He predominantly focuses on animals as tools for training human virtue (e.g. poisonous animals) or as examples of the incomprehensibility of divine mystery (e.g superfluous animals). Yet Augustine's returns to Genesis also lead him to acknowledge a commonality between humans and animals, namely the experience of bodily pain (cf. Cizewski 1993). This paper explores the transgressive limits of physical pain and animality as it is addressed in his three Genesis commentaries and The City of God. I bring Augustine's interpretations into conversation with Deleuze and Guattari's concept of “becoming animal,” or affective non-identity. I argue that his analyses of Genesis cause him to develop a concept of physical pain that can be more properly understood as affect, or the capacity to affect and be affected that precedes emotion and subjectivity itself. In this fashion, Augustine's understanding of bodily pain is unlike [a] the traditional Stoic passions (e.g. distress), which are preceded by internal stimuli, or [b] propatheiai, reflexive reactions that stem from a cognitive source, which for him was doubt (Byers 2013). Bodily pain has no antecedent and is shared between human and animal alike; it causes a disintegration of the unity of the soul and body, the self-dissolving reaction of “becoming animal.” This shared capacity raises questions about the limits of Augustine's own categories of human and animal, as well the concept of the self as such.