While agency has received considerable attention in recent sustainability transitions studies, as well as in the literature on socio-ecological systems and sustainability transformations, the focus has been on the agency of humans. Given the emphasis on infrastructures and material culture in sustainability transitions studies, it is surprising that non-human agency has not received more attention. This paper aims to add to the body of work on agency and actor-oriented approaches in sustainability transitions, and addresses this gap by investigating the role of non-human agency in shaping sustainability transitions. Through an application of Actor-Network Theory, we followed the Bagrada hilaris pest, and analyzed the roles performed by the Bagrada as a so-called actant within a network of humans, as part of a transition-in-the-making towards more sustainable food systems. The Bagrada has been a key actant in provoking changes towards sustainable pest management in Chile, destabilizing regime practices associated with pesticides, and creating and mediating relationships between different human actors. In terms of transition theories, particularly the multi-level perspective, this case illustrates the relational nature of agency. The main theoretical implications are that: a) actants from all levels (niche, regime, landscape) are linked in networks of relations that make change happen; b) the landscape level is not void of agency; c) boundaries between levels are fluid. We conclude that relating to non-human actants and understanding how to mobilize them for normative goals can help catalyze sustainability transitions.