This episode of "This American Life," co-hosted by Ira Glass and Fred Armisen, explores the theme of doppelgangers through two main acts. Act One investigates the rumor of pork bung being passed off as imitation calamari, with reporter Ben Calhoun interviewing various sources, including pork industry insiders and food experts, to uncover the truth. Despite a lack of definitive proof, the segment delves into the possibility and the psychological implications of such a substitution. Act Two presents a comparison between a veteran from Afghanistan and a man from a violent neighborhood in Philadelphia, highlighting the similarities in their experiences with trauma, constant vigilance, and the challenges of reintegration, illustrating how different environments can produce similar psychological effects.