One of the most successful tactical innovations of the Vietnam War was the introduction of the F-100 Super Sabre to perform the new mission of "Fast FAC" (Forward Air Control). Under the call sign of "Misty," F-100F pilots interdicted equipment and supplies flowing into South Vietnam. Their story is important because it provides key insights into how the Air Force flies, fights, and adapts during combat. This article reviews the early years of the Vietnam War and how the need for Fast FACs evolved. Prior to the spring of 1967, the USAF tasked O-1 and O-2 FACs to conduct visual reconnaissance missions over the southern area of North Vietnam. In response, the North Vietnamese deployed additional air defenses, driving the slow and vulnerable propeller-driven aircraft back across the border. Operation Commando Sabre was the first test of the Fast FAC concept. Jet aircraft would perform FAC duties, adapting the two-seat version of the F-100 Super Sabre to the visual reconnaissance and strike control mission. This article also highlights the build-up and operations over the Misty FACs three-year history until the unit's dissolution in May 1970. Commando Sabre operations never consisted of more than twenty-two pilots at any given time and rarely involved more than six single-ship missions per day. Yet, they succeeded in finding and destroying targets where other methods had failed. This success came at a price, though, as the low altitude Misty FAC missions proved to be among the most dangerous missions flown in the Vietnam War. Nonetheless, the tactics developed by the Misty FACs--including visual reconnaissance, strike control, and search and rescue operations--formed the foundation for FAC and Killer Scout operations employed during Operations Desert Storm and Allied Force, and remain valid today.