The presentation reflects on theories of performative speech acts from the British philosopher of language J.L. Austin's “How To Do Things With Words” (based on a series of lectures in the 1950s). Using Austin's notion of “parasitic” language of an actor on the stage as a starting point, the paper analyses the Japanese Robot-Human Theatre production “Hataraku Watashi” (I, Worker) by Hirata Oriza and Ishiguro Hiroshi from 2008 as a site for investigating the complex layers of intention, effect and cultural conventions in human-robot interaction. Linking the fiction of the stage production to laboratory testing that include robots in simulated real-life situations, the notion of how robots “lie” are discussed in terms of different types of participants: theatre audiences and test persons. The presentation will focus on how the robot acts “parasitic” upon normal circumstances and thus points out the troubled notions of “normal” or “natural” in robot-human interaction, as well as in human-human interaction.