(source Wikipedia) The 1st Special Service Force (also called The Devil's Brigade), was an elite American-Canadian commando unit in World War II, under command of the United States Fifth Army. The unit was organized in 1942 and trained at Fort William Henry Harrison near Helena, Montana. The Force served in the Aleutian Islands, and fought in Italy, and southern France before being disbanded in December 1944.
General Frederick had cards printed up with the unit's insignia on them and the words Das dicke Ende kommt noch! or "The worst is yet to come" printed in red ink down the right side which the force would leave on the bodies of dead Germans as a form of psychological warfare.