MUSCATATUCK URBAN TRAINING CENTER, Ind. " Mike "Caveman" Spina, is one of the civilian role players at Vibrant Response 13. During this exercise the role players portray "displaced civilians" in the aftermath of a "simulated" nuclear attack on a major Midwestern city. He has worked as a role player for military exercises around the United States for the past six years. Vibrant Response 13 is a major incident exercise conducted by U.S. Northern Command and led by U.S. Army North.