My grandfather served on the Western Front during World War II, but he actually got there too late for the fighting. He was one of the final wave of soldiers that went over to Europe, and his military service was limited to the post-war occupation of Germany. I asked him once if he ever saw combat, and he said not really, but that his unit was pinned down by sniper fire once.
That sniper would have been a “Werwolf,” part of a last-ditch attempt by the Nazis to carry out a guerrilla campaign against the victorious allies, imitating the methods of the partisan forces that had been making things difficult for the Nazis themselves on the Eastern Front and elsewhere.
The idea of the Werwolf campaign was not to stage an ongoing guerrilla war after the Allies won, because the Nazis just couldn't accept the possibility that such a thing could even happen in the first place. What they were really supposed to do was just to slow the Allies down until the Nazis could recoup their losses and stage a massive counterattack, which at that point was just a fantasy. But Werwolf units were trained in guerrilla warfare, and some of them did try to continue the struggle after Germany's surrender.
They planted bombs and cut railroad tracks and staged sniper attacks from rooftops, like the one my grandfather ran into. It had no chance at all of success, but such was the intense fanaticism of some of the Nazi true believers.