We analyze the behavioral determinants of extreme punishment in intergroup conflict. Individuals contribute to team production by a tedious real effort task. Teams compete for a prize in asymmetric tournaments. Asymmetries are implemented as differences in the time available to complete the task and are generated by nature or by the decisions of one group, arbitrarily chosen. Relative to a symmetric baseline condition in which groups have identical time to complete the task, we study two different types of inequality: economic (one group gets more time than the other, chosen by nature) and political (one group determines how much time the other group is given). We allow for a particular form of intergroup punishment. Individuals in the disadvantaged group may attack and punish all individuals in the other group (thereby reducing their earnings by half) at an extreme price: if they decide to punish the other group, the disadvantaged group member must sacrifice all of their individual earnings. Our results strongly support the link between political asymmetries and extreme intergroup punishment. Relative to a control treatment with no asymmetries, economic inequality has no significant effect on the likelihood of intergroup punishment. However, there is a great deal of punishment in the political inequality treatment, where one group can actively oppress the other. Advantaged groups make very limited use of a conciliatory transfer, only marginally reducing punishment from disadvantaged groups. Interestingly, we find that skilled individuals are more likely to sacrifice themselves to harm the other group.