We hear so much about extinction in debates around climate change. But what about those animals that go feral and then return – bigger, hungrier and angrier – to wreak revenge on humans who may have done them injustice? Using an eco-postcolonial framework, this article examines how a number of exploitation horror films have dealt with environmental topics and issues of trespass. In particular, I examine the agency of animals – crocs, pigs, thylacines and marsupial werewolves – in some key Australian eco-horror films from the last 30 years: Long Weekend (Eggleston, 1978), Razorback (Mulcahy, 1984), Dark Age (Nicholson, 1987), Howling III: the Marsupials (Mora, 1987), Rogue (Greg McLean, 2007), Black Water (Nerlich & Traucki, 2007) and Dying Breed (Dwyer 2008). On the one hand, these films extend postcolonial anxieties over settler Australian notions of belonging, while on the other, they signify a cultural shift. The animals portrayed have an uncanny knack of adapting and hybridizing in order to survive, and thus they (the films and the animals) force us to acknowledge more culturally plural forms of being. In particular, these films unwittingly emphasize what Tim Low has termed the ‘new Nature’: an emerging ethic that foregrounds the complex and dynamic interrelationships of animals with humans.