The X-files 11x6 -
In the X-Files episode (Season 11, Episode 6), Walter Skinner's mysterious past in the Vietnam War finally takes center stage. The episode explores themes of guilt and accountability, revealing how a secret military project called MK-NAOMI —a gas designed to induce extreme fear and hallucinations—shattered Skinner's faith in the government. Plot Summary
: The investigation leads Mulder and Scully to Mud Lick, Kentucky, where people are being murdered in booby traps resembling Vietnam War punji pits. The X-Files 11x6
According to reviewers from IndieWire , this episode provides a "sweet and touching" moment for Skinner that feels earned after 20 years of backstory. In the X-Files episode (Season 11, Episode 6),

