This article describes teachers' collaborative inquiry into the pretend "bad guy" play of 12 children in a university laboratory preschool classroom in the northeastern United States. The article describes the inquiry process and includes details and documentation of children's decisions, actions, and interactions related to the bad guy play as well as the teachers' reflections taken from field notes, meeting notes, and journals. Among the conclusions drawn by the teachers are that (1) children's pretend play can become complex when teachers support but do not direct it, (2) teachers' discomfort with certain play themes might inhibit play that could be valuable to children, (3) children's pretending to act aggressively is not the same as acting aggressively, and (4) play has a rhythm and structure that can be better understood through documentation and reflection. (Contains 8 figures.)