On 15 August 1944, an Allied army launched a second amphibious landing against the coast of southern France. The Allies, having shattered German defenses around the beachhead, decided to exploit the chaos in the enemy camp. On 17 August 1944, Major General (MG) Lucian K. Truscott Jr., with no mobile organic strike force assigned to his VI Corps, ordered the assembly of and attack by an ad hoc collection of units roughly equivalent to an armored brigade. This provisional armored group (Task Force (TF) Butler) experienced remarkable success despite a dearth of planning, no rehearsals, and no history of working together in either training or combat. This case study examines the success of TF Butler from the perspectives of doctrinal development in the United States (U.S.) Army, the unit’s unique task organization, and the leadership’s employment of the unit in combat. The use of ad hoc formations to meet unforeseen situations was not unique to World War II; American units currently serving in the Middle East are regularly assigned units they have no habitual relations with to conduct combat operations. This case study may prove useful in preparing contemporary military leaders for the types of challenges they will face conducting operations in the contemporary operational environment.