The Boys from Brazil (1978)

A Nazi hunter comes out of retirement and finds out that somebody's cloning Hitler. The Nazi hunter and the main Nazi (Laurence Olivier?) fight and basically kill each other, at which point little-boy Hitler shows his true Hitler colors and is creepy and sadistic. It's very possible that this movie ends with the Hitler clones healthy and free. Something happens with a dog—maybe a Hitler dog, like the Hulk dogs in Ang Lee's Hulk? I kid.

See what they did there with the mirrors? Cloning humor.