The 957-A3 was a locally-produced variant of the M808B Scorpion tank in service with the UNSC during the Human-Covenant War. It was codified by the UNSC Army. The tank featured enhanced electronics for more accurate firing. As well as it modifications, it had what appeared to be an arrowhead or lambda symbol painted on its left front tread cover.
In 2552, a 957-A3 was assigned to the UNSC In Amber Clad. In November of that year, during the Battle of Earth, the tank was deployed in the industrial zone of New Mombasa to defend a Lethbridge Industrial building housing A Company from Covenant forces. Shortly after John-117 arrived, a Scarab walker started to advance on their position. The 957-A3 used its main cannon to fire on the walker, but to no avail. Within seconds, the Scarab's focus cannon destroyed the tank, killing the vehicle's operator.
- It is possible to save this tank from destruction. When arriving in this area to destroy the Type-26 Wraith, steal a Type-32 Ghost and keep it alive. When the door opens to let you into the building, take the Ghost inside. With a little time and patience, you can get the Type-32 Ghost (or a Warthog) to the roof. Once on the roof, drive off and get to the tank as soon as possible. Get in the tank and move it straight back. If you are quick enough, the Scarab will not fire, and the tank is saved. Also, if the tank's operator survives, he will appear to be holding an invisible firearm.
- In the Halo 2: Anniversary map Bloodline—the remake of Coagulation—the 957-A3 is replaced by the 957-A4.