Virologists have long thought of baculoviruses, a group of viruses that can liquefy their insect hosts in a matter of days but don't induce so much as a sneeze in mammals, as potential pesticides. But the viruses would require tweaking to be effective since they kill insects more slowly than chemical insecticides. Studying baculoviruses also yields insights into general viral behavior. The current study examined how baculoviruses took the evolutionary leap needed to become the nasty bugs they are today.