Drawing on reflections from a collaborative autoethnography, this article argues that ultramarathon running is defied by a 'dark' ecological sensibility (Morton 2007, 2010, 2016), characterised by moments of pain, disgust, and the macabre. In contrast to existing accounts, we problematise the notion that runners 'use' nature for escape and/or competition, while questioning the aesthetic-causal relationships often evinced within these accounts. With specific reference to the discursive, embodied, spatial and temporal aspects of the sport, we explore the way in which participants (...) begin to appreciate the immense power of nature, while being humbled by the fragile and unstable foundations of human experience. Accordingly this article contributes novel insights into the human-nature complex that seek to move beyond Romantic analyses towards a more sophisticated understanding of the relationships between (nature) sport, people and place. (shrink)