Question: Operation "Greif" was a special operation during a battle where which forces incurred their  highest casualties of any operation during the war ?
Sentence (from "Operation Greif"): Operation "Greif" (German: "Unternehmen Greif" ; ] , meaning "Griffin") was a special operation commanded by Waffen-SS commando Otto Skorzeny during the Battle of the Bulge in World War II.
Relevant evidence: Yes