This film was played at an animation showcase my siblings and I recently attended. We fell in love with it, if only because of how thoroughly horrific the last few minutes are. It's a stop-motion short film that was made by Norman McLaren in 1969. You will go to jail if you can't guess the moral of the story.
“You must not kill your neighbor, whom perhaps you genuinely hate, but by a little propaganda this hate can be transferred to some foreign nation, against whom all your murderous impulses become patriotic heroism.” Bertrand Russell