The Ersatz M10 was built with the purpose of mimicking the American M10 tank destroyer. It was a result of a German plan during the Operation Watch on the Rhine. The plan consisted of sabotaging American and British forces as much as possible before the "Battle of the Bulge". The plan required the use of German soldiers armed and fitted with American and British gear, captured Allied tanks, jeeps, APCs, and trucks. However with very short time to prepare, low supplies of captured gear and other issues, the Germans disguised their Panther tanks to look like American M10 Tank Destroyers. Although in the greater scheme of things the operation was not successful, as no important areas were occupied, the Ersatz M10 did manage to cause paranoia in Allied forces, making them unable to safely identify Allied M10s from disguised Panthers from a distance, resulting in several friendly fire incidents. However, these incidents were not enough to change the course of the battle.

It was introduced in Update 1.75 "La Résistance" as a reward for the 2017 "Festive Quest" event. The Ersatz M10, performance wise, is the same as a Panther Ausf. G in terms of armour layout but with the automotive power of the Ausf. A. The tank packs a powerful 75 mm KwK 42 cannon and has very good armour protection at the front of the turret but especially in the hull, thanks to its sloped armour design. The vehicle suffers from a poor turret rotation speed and a very mediocre reverse speed of only 4 km/h, which is not enough to retreat during dangerous situations. With the ammo stacked at the sides of the vehicle, carrying just the minimal amount is recommended to avoid ammo detonation. The poor reverse speed requires this tank to be played cautiously: sniping at long ranges or advancing with allied coverage is a good way of using this vehicle. It is also possible to shoot while on the move even in uneven terrain, although it might require some skill, thanks to the suspension of the tank, that allows for relatively smooth driving when compared to other tanks around its BR.