Fan Casting "I've seen what you can do. I've been watching you" in Justice League: Year One

All of the heroes are kind of hypnotised and they gather in an abandoned building. There, they meet with a martian named J'onn J'onzz, who tell them he's been watching what they can do. The heroes are all confused, so he transforms into the alter egos he’s adopted: David Snigh, Rupert Jones, Elizabeth Lewis, Bao Huang. They think he's a threat, but change their minds when J'onn tells them his planet was destroyed because of Brainiac and is looking for revenge.