Samuel Beckett’s corpus centres on the characterization, examination and imaginative exploration of the human mind, encompassing the realms of consciousness, cognition and perception. In his teleplays, this focus is distinctively achieved through the performances of different media, which this article refers to as ‘intermedial performativity’. This term not only designates the semiotic contents of performance in intermedial forms, but also highlights the cooperative performances of the material media themselves, along with their uncharted possibilities and effects. This article delves into the ways in which intermedial performativity in Beckett’s teleplays realizes several unique configurations of the human mind, such as its split state and its transfiguration to a posthuman condition. This exploration not only sheds light on Beckett’s artistic vision and cosmic ontology, but also brings attention to the reverberations and implications of intermediality for humanity and its potential transformations.