What will it take to undomesticate the world—to begin to loosen humanity’s tight grasp on the planet’s spaces, structures, resources, and populations? Marie Darrieussecq’s short story “My Mother Told Me Monsters Do Not Exist” describes the intrusion of an unidentifiable creature into a fastidious woman’s apartment home, a modest but powerful scene of undomestication. This brief tale illustrates the intertwined forces of domestication and feralization that link humans and animals and proposes interspecies companionship as a lively and productive site of ferality in the regimented unwildness of the Anthropocene.