Environmental variation is a constant. Difficult to predict but important ‘Black Swan’ events are increasing in frequency and magnitude, but we are only beginning to understand the ecological and evolutionary consequences of such events. Extreme events can increase or decrease eco-evolutionary heterogeneity depending on the spatial grain at which they occur. Here I present a 6-year study of 3000+ individual univoltine gall makers and their enemies from 15 populations. An extreme event in one generation homogenized a key environmental determinant of enemy attack rates and survival, but exposed gall makers to an alternative environmental driver of ecological interactions. Counterintuitively, rather than acting as an ecological or evolutionary filter, extreme events can create greater spatial variation in demography, species interactions, natural selection, and evolutionary change. I suggest that the eco-evolutionary consequences of Black Swan events can only be understood by considering the evolutionary outcome of what are often complex species interactions.