This paper puts forward a model of theatricality as the protean experience in hybridized forms of contemporary art. The author focuses on artistic events that fuse not only different artistic media but also scientific and political discourses and practices of designing new technologies. In the first part of the article, the author employs the theoretical findings of the German art theorist Juliane Rebentisch to critically examine the concept of theatricality as establishing a hierarchical relation between human subjects and non-human objects of aesthetic experience (Fried). As Rebentisch succinctly observes, the theatricality of installation art becomes an open space of experience in which experimental relations between subjects and objects emerge without any pre-established hierarchy. In the second part of the article, the author problematizes the question of spectatorial experience by referring to new materialist philosophies (Barad, DeLanda, Sabolius) which posit a non-anthropocentric model of experience as an assemblage of different human and non-human elements. From this perspective, the author formulates a concept of theatricality as the protean experience which entails the constant change of status of all human and non-human participants of the artistic events. Theoretical findings are illustrated not only by analyses of particular artistic strategies but rather by experiences of participants in contemporary installation art.