EpisodeReplaceable You99% Invisible · Sep 16, 2025 · 34 minPlay · 34:02SaveShareEpisode pageMary Roach dives into the strange, funny, and unsettling world of designing new body parts, from pig hearts to prosthetic feet, revealing just how messy replacing ourselves can be.RelatedEpisodes 1Books 4How to be less neuroticThe Gray Area with Sean Illing • Sep 7, 2026 • 40 min