Have him go undercover as a mole in the Justice League

"By my analysis, you will be more useful as a pawn. You will infiltrate the Justice League and assist me in crippling them from the inside." Three monitors appeared before him. "As a gesture of good will, I will allow you to choose which form I will mold your body into." One of the screens showed an image of Wonder Woman and some videos playing of her in action. The second was similar just it showed off Zatanna and the third was of Power Girl.

"What makes you think I would betray the Justice League?"

"You are not one of them. You are viewed as inferior. And you are interested in your own self-preservation. As I stated previously, it is in your best interest to rule this universe by my side. Your mind will be of far greater use to me in tact. Capable of free thought. Now choose."