A heat seeking missile decoy device mounted on a military vehicle to change the infrared signature of the military vehicle. The device is at ambient temperature when stored on the military vehicle. When a heat seeking missile is fired at the military vehicle, the decoy device deploys and increases in temperature, changing the infrared signature of the vehicle and causing a hot spot away from vulnerable components of the vehicle. The hot spot radiates in the infrared in an area that is away from vulnerable parts of a military vehicle, drawing the heat seeking missile toward it. The termination trajectory of the heat seeking missile is at the end of the decoy device and not the vulnerable parts of the military vehicle. The energy required to heat the device is passive waste energy from the vehicle engine exhaust.