Der Fuehrer's Face (1943)

A marching band of Germans, Italians, and Japanese march through the streets of swastika-motif Nutziland, serenading "Der Fuehrer's Face." Donald Duck, not living in the region by choice, struggles to make do with disgusting Nazi food rations and then with his day of toil at a Nazi artillery factory. After a nervous breakdown, Donald awakens to find that his experience was in fact a nightmare.