An increasingly influential approach to solving human ecological problems is an innovative design practice known as biomimicry. The Biomimicry Institute, a major stakeholder in the Biomimicry Movement, promotes biomimicry as a practice that mimics nature’s genius to solve human challenges and provides hope of sustainable futures. Despite increasing global interest in the practice, so far little is known about the value placed on biomimicry within practitioner communities. Employing a corpus-assisted discourse-analytic approach, this paper explores the ways video narratives shared by practitioners affiliated with and curated by the Biomimicry Institute position biomimicry as a sacred practice. Drawing on Stibbe’s ecolinguistic approach and Hobbs’ functional religious language framework, we observe an overarching discursive pattern of conversion narrative (incorporating both personal and collective storylines) which highlights the sacred significance of the movement. We explore how the linguistic strategies underlying these conversion narratives centre human experience, mark group identity and attract new converts, while constructing an ecologically ambivalent discourse. In particular, we find that use of vague language obscures the precise nature of involvement in the movement and blurs the lines between member and non-member, contributing to the conversion narratives’ potential as powerful proselytising tools.