Peace on Earth is a “one-reel 1939 Metro-Goldwyn-Mayer cartoon short directed by Hugh Harman, about a post-apocalyptic world populated only by animals.” It is an anti-WWI protest film, that was nominated for an Oscar, and may have been considered for a Nobel Peace prize nomination.
Mel Blanc does the voice of the grandfather squirrel. On Christmas he greets his grand-squirrels with a cheery “Peace on Earth, goodwill toward men!,” and the curious children ask him, “What are men?” The grandfather explains:
Grandpa Squirrel: Good will to men, yes, good will to men.
Baby Squirrel 1: What are men, Grandpa?
Baby Squirrel 2: Yeah, Grandpa, what are men?
Grandpa Squirrel: Huh? What’s that?… Well there ain’t no men in the world no more, sonnys… nope, no more men. But as I remember the critters, well they was like monsters. They wore these big metal pots on their heads. They walked on their hind legs, and they carried terrible-looking shootin’ irons with knives in the end of them. Their eyes gleamed, and they had these tremendous big snoots, like this, that curled down and fastened down to their stomachs.
Baby Squirrel 1: Gee! I’m glad there ain’t no more men around.
Baby Squirrel 2: Me too.
Grandpa Squirrel: It was awful. It was terrible. Why, they fought and they fought and they fought, until… until there was only two of them left.
[each soldier shoots the other and goes down]
Grandpa Squirrel: And that was the end of the last man on Earth.
Peace on Earth was remade into Good Will to Men in 1955. Good Will to Men features a group of young mice attending a service led by an old and wise mouse, in the ruins of a church. This time, when the children ask about ‘men,’ the old mouse bluntly replies, “Too bad they didn’t practice what they preached.” He explains that men killed each other off by using ever and ever more sophisticated war technology.