Mitchell glanced at him and tried to contact the Gamma Site but received no response. After Mitchell left the cave, Walker scratched his neck, and a small R-75 bug crept underneath his skin. The next morning he was absent from his post at the front of the cave, and Teal'c, Dr. Daniel Jackson and Lt. Colonel Cameron Mitchell went searching for him. Daniel then discovered Walker's dead body and hundred of bugs poured out. (SG1: "The Scourge")