An aggressor squadron or adversary squadron (in the US Navy and USMC) is a squadron that is trained to act as an opposing force in military wargames. Aggressor squadrons use enemy tactics, techniques, and procedures to give a realistic simulation of air combat (as opposed to training against one's own forces). Since it is impractical to use actual enemy aircraft and equipment, surrogate aircraft are used to emulate potential adversaries. The first formal use of dissimilar aircraft for training was in 1968 by the Navy Fighter Weapons School (better known as "TOPGUN"), which used the A-4 Skyhawk to simulate the performance of the MiG-17. The success of formalized dissimilar air combat training (DACT) led to transition of Navy Instrument Training Squadrons equipped with the A-4 into Adversary