:This article analyzes a specter that has haunted bioethics almost since its inception, namely the specter of the misuse of biotechnology by maleficent agents bent on mass destruction, or the complete eradication of human kind and life as we know it. The article provides a general account of why bioethicists cry “catastrophic bioterrorism potential” when new biotechnologies emerge, and an analysis of the arguments that flow from the prediction, especially in relation to synthetic biology.