My topic is the possibility of acting in the belief that the action is bad and for the reason that it is, as the agent believes, bad. On route, I examine another question – namely whether agents can, without having any relevant false beliefs, perform actions motivated by the badness of those actions. The main worry is the compatibility of action for the sake of the bad with the thesis of the Guise of the Good (roughly that actions undertaken with an intention to perform them are undertaken because they are, as the agents see things, good in some respects). The examina-tion is helped by considering the way reason explanations and the more widely understood normative explanations can explain actions, in light of the conditions for the rationality of actions and the bearing of masking beliefs (broadly: self-deceived beliefs that mask the agents’ true motives or reasons from them) on the explanation of their actions. The discussion leads to consideration of the possibility of various conceptual mistakes. Given the variety of human motivations, I focus on the interpretation of one case: the Luciferian motive, understood, roughly, as the drive to defy the limits of thought or of rational thought.