During the first decades of the 20th century, a renewed sensibility for different religious traditions distinguished German(-language) Expressionism, and especially Expressionist drama. It has long been accepted that Expressionism is characterized by a Judeo-Christian ‘Messianic’ scope. Scholarly research, however, mainly ignored that Expressionist drama also recurs to Greco-Roman and Oriental rituals in the performance of an initiatory-pedagogical experience of transformation. Paradigmatic of this reception are the plays of Oskar Kokoschka, Walter Hasenclever, Franz Werfel and Reinhard J. Sorge. In this experience, presented as a ritual act, a protagonist ‘forms’ and converts himself in an initiatory process of destruction and transformation. ‘Form’ adapts both a classical ‘Bildungs’ideal and the Dionysian view on transformation as a generative force, primarily mediated by Nietzsche. In critical essays and journals these authors reflected on the dramatic form in religious terms, expressing the hope that drama would serve as a modern religion. In this way, 'form' has poetological implications as well. Although Expressionism has been primarily associated with form destruction and radical modernity, I will argue that Expressionist drama’s syncretic reception of ancient initiatory rituals and mystery cults requires a redefinition of form as a creative-pedagogical concept, to which these dramatists attributed a reformatory potential both on the personal and social level.