This presentation argues that filmmaker’s Seto Momoko’s experimental shorts, Planet Sigma (2014) and Planet Infinity (2017) present a magical-speculative vision of post-extinction worlds while at the same time articulating a subtle immanent critique of anthropocenic imaginaries in the humanities and visual culture. This critical vision is expressed mainly through three strategies: 1)The staging, by means of “magical” techniques such as time-lapse photography and VR (virtual reality), of uncanny, primordial toxic worlds; 2)the foregrounding of the agency and potentiality of in/nonhuman non/life and forces; 3)a dispassionate, post-or nonhuman perspectivism that displaces the postapocalyptic horror and epic survivalism in much “Anthropocenema” as well as the techno-fix optimism of some eco-documentaries. These strategies are in turn sustained, in the two films under discussion, by several experimental techniques and aesthetic choices: outsized scale (e.g. the frozen insects that come back to life in Planet Sigma are gigantic); a processual poetics of repetition and loops; an insistence on the surplus-value-of-alterlife. Building on the emerging science of evolutionary mineralogy, immanence philosophies, and recent feminist decolonial non/posthuman discourses, I will show that Seto’s films envision post-extinction worlds as a radical ecology of indefinite, nonhuman alterlife (already altered life) that not only challenges the humanist hubris and anthropocentricism of Anthropocene science but also insists that the crucial agency of the “tangled geochemical continuum” of life and nonlife in building the planet’s systems requires a reconceptualization of the notion of life and of its materialities and temporalities.