This empirical and doctrinal study of copyright trolling presents new data showing the astonishing rate of growth of multi-defendant John Doe litigation in United States district courts over the past decade. It also presents new evidence of the association between this form of litigation and allegations of infringement concerning pornographic films. Multi-defendant John Doe lawsuits have become the most common form of copyright litigation in several U.S. districts, and in districts such as the Northern District of Illinois, copyright litigation involving pornography accounts for more than half of new cases. This Article highlights a fundamental oversight in the literature on copyright trolls. Paralleling discussions in patent law, scholars addressing the troll issue in copyright have applied status-based definitions to determine who is, and is not, a troll. This Article argues that the definition should be conduct-based. Multi-defendant John Doe litigation should be considered copyright trolling whenever it is motivated by a desire to turn litigation into an independent revenue stream. Such litigation, when initiated with the aim of turning a profit in the courthouse as opposed to seeking compensation or deterring illegal activity, reflects a kind of systematic opportunism that fits squarely within the concept of litigation trolling. This Article shows that existing status-based definitions of copyright trolls do not account for what is now arguably the most prevalent form of trolling. In addition to these empirical and theoretical contributions, this Article shows how statutory damages and permissive joinder make multi-defendant John Doe litigation possible and why allegations of infringement concerning pornographic films are particularly well-suited to this model.