Superman: The Animated Series S03E06 - Absolute Power

Jax-Ur and Mala have escaped from the Phantom Zone and have subjugated an entire planet, ironically dubbing it "New Krypton." After rescuing a distraught spaceship from a black hole, Superman stumbles upon New Krypton. At first, he feels he should leave Jax-Ur and Mala alone to rule as they please, but he reconsiders when he sees they are secretly creating a navy with the intent of attacking Earth.