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.
