Nature is often violent and unforgiving, but few understand the extent to which animals engage in behaviors that, if judged by human ethical standards, would be considered malicious, immoral, or even evil. This provocative course will challenge our understanding of morality through the lens of non-human behaviors. Throughout this course, you will uncover the ecological and evolutionary underpinnings of seemingly malevolent behaviors, including predatory play, surplus killing, infanticide and siblicide, traumatic insemination, sexual coercion, sexual cannibalism, brood raiding, brood parasitism, host manipulation, resource hoarding, chemical warfare, inter-colony elimination, and unprovoked lethal violence. We will examine the implications of applying anthropocentric ethical standards to the interpretation of animal behaviors, fostering a nuanced understanding of nature’s diversity. This course is designed for students who are eager to engage with the complexities of animal behavior from a critical and evolutionary perspective. Participants will gain a deep appreciation for the intricacies of the animal world and the ability to critically assess the anthropomorphism of animal actions. Prepare to challenge your perceptions and sensibilities as we explore the darker side of nature in a course that will be as controversial as it is captivating.