The plaster cast collection of the Glasgow School of Art (GSA) has formed a key part of the institution’s history and experience ever since the School was founded in 1845, and in the aftermath of the 2014 fire in the Mackintosh Building, their impact was transformed. Framing the damaged casts as active agents in tangible and intangible heritage, this paper argues that their patina of experience adds new weight and impact to their object biographies, and that these ecologies of meanings further developed after the second fire of 2018. First, I draw upon archival materials held at the GSA Archives and Collections to unpack patterns of acquisition and provenance. Then, I outline some of the key drivers for the use of the casts in teaching, focusing on the period of Francis Newbery’s directorship. Next, I draw insights from the conservation project on some of the damaged casts after the fire of 2014, with discussion of their dramatic appearance and impact. Finally, I consider ideas of value, reproduction and aura, and how, in the case of these non-human actors, loss becomes the catalyst for a strikingly new experience.