This paper explores the "social movement learning" operating within one site of critical public pedagogy and, specifically, examines how the anti-consumption activist group "Reverend Billy and the Church of Stop Shopping" encourages transitional spaces of learning through a "pedagogy of the unknown." Bill Talen, a.k.a. "Reverend Billy", is an anti-consumption activist who utilizes performance art as a form of critical public pedagogy. Through an analysis of his performances gathered from numerous sources including video, audio interviews and written scripts, this paper discusses how Reverend Billy's work operates as a form of critical public pedagogy. This paper posits that Reverend Billy: (1) deliberately tries to avoid categorizing himself, so he remains a kind of "uncategorizable" pedagogue and "unknowable" preacher who (2) preaches against the "known" consumerist script, he (3) enacts a pedagogy of the unknown and "performs" the unknown, as he focuses on asking questions and enacting "exalted acts of embarrassment" that are unsanctioned in everyday life to (4) disturb customers long enough so that they can (5) back away from the product, away from the consumerist script, into what Reverend Billy calls "the fabulous unknown". This pedagogy of the unknown seeks to open the "transitional spaces" so necessary for critical learning about consumerism to take place. (Contains 1 figure and 4 notes.)