Operation Greif was a special false flag operation commanded by the notorious Waffen-SS commando Otto Skorzeny during the Battle of the Bulge.
The operation was the brainchild of Adolf Hitler, and its purpose was to capture one or more of the bridges over the Meuse river before they could be destroyed. German soldiers in captured US Army uniforms and using some US vehicles were to cause confusion in the rear of the Allied lines. A lack of vehicles, uniforms and equipment limited the operation and it never achieved its original aim of securing the Meuse bridges.
Skorzeny had become one of Hitler's favorites following the success of "Operation Eisenfaust" in which he had supervised the kidnapping of Miklós Horthy, Jr., the son of Hungary's Regent, Admiral Miklós Horthy to force Horthy's resignation. Following his return to Germany, Skorzeny was summoned to meet Hitler at his headquarters at Rastenburg (Ketrzyn) in East Prussia on 22 October 1944. After congratulating Skorzeny and announcing that he had been promoted to Obersturmbannführer, Hitler outlined the planned Ardennes Offensive and the role he was to play in it.
Skorzeny was to form a special brigade - Panzer Brigade 150 - whose purpose would be to capture one or more of the bridges over the Meuse river before they could be destroyed. Hitler informed him that he had decided this could be accomplished more quickly and with fewer losses if Skorzeny and his men wore US uniforms. Hitler also remarked that small units in enemy uniform could cause great confusion among the enemy by giving false orders, upsetting communications, and misdirecting troops.
I want you to command a group of American and British troops and get them across the Meuse and seize one of the bridges. Not, my dear Skorzeny, real Americans or British. I want you to create special units wearing American and British uniforms. They will travel in captured Allied tanks. Think of the confusion you could cause! I envisage a whole string of false orders which will upset communications and attack morale.
”— Adolf Hitler
6th Corps Combat Engineers