This article explores how breakthrough neuroscientific research regarding the Microbiome-Gut-Brain-Axis (MGBA) resonates with Catherine Malabou’s discussions of a delocalised, decentralised, plastic brain. Inspired by Malabou’s materialist methodology, as well as her confrontation of neuroscientific and psychoanalytic paradigms, the article unpacks the imbrication of symbolic and neuro-microbiological treatments of the gut and its excreta. Interlacing the thought of Julia Kristeva, Melanie Klein and Malabou alongside current MGBA research and critical studies of science and technology, I reveal how symbolic and microbial transmissions in early childhood development reflect a multimodal and multitemporal formation that challenges the established imaginary associated with functional gut and subject development. Secondly, I consider how MGBA research bears upon questions of difference, examining its further materialisation of Malabou’s otherness in a world without exteriority. Through this discussion I question the significance of this biological paradigm shift, as it disturbs notions of agency and the subject/environment distinction, opening to pressing ethical questions at this moment in human history. Through these varied interrogations and provocations, I provide a preliminary window into the potential of MGBA research to enable new departures for thinking the fragmentary movement of form and time underpinning Malabou’s motor schema of plasticity.