In 2005, a mysterious plague called Corrupted Blood hit the online denizens of World of Warcraft, ripping through cities and decimating player characters. After the smoke cleared, it became clear that this virtual plague shared many characteristics with real-world diseases and almost immediately attracted the attention of researchers. In this Summer Short, I go over the details of the in-game Corrupted Blood incident, and the very real-world epidemiological research that followed. Learn about all this and more on the latest short of Bedside Rounds, a tiny podcast about fascinating stories in clinical medicine.   Sources: Bohannon J. Slaying monsters for science. Science  20 Jun 2008. Messner S. How Blizzard coped with World of Warcraft's blood plague and other early disasters. PC Gamer. Henderson M. Analysis: Absence of risk limits parallels with real life. Times Online. October 28, 2008 Oultram S. Virtual plagues and real-world pandemics: reflecting on the potential for online computer role-playing games to inform real world epidemic research. BMJ. Lofgren E, Fefferman N. The untapped potential of virtual game worlds to shed light on real world epidemics. Lancet Infect Dis 2007;9:625–9.