Final answer:
The decisive battle that took place in December 1944, one spring before the end of Hitler's reign, where Mel Brooks fought, is known as the Battle of the Bulge. This was one of the largest and most severe battles fought by the United States during World War II.
Step-by-step explanation:
The battle being referred to in the question is the Battle of the Bulge, which took place in December 1944. It was a major German offensive campaign on the Western Front during World War II, and it was one of the largest and bloodiest battles fought by the United States during the war. Mel Brooks, an American comedian, actor and film producer, was also a combat engineer during the war and took part in the Battle of the Bulge. This battle was decisive as it exhausted much of Germany's remaining war potential thus signaling the beginning of the end for Hitler's reign.
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