Aatrox, The Darkin Blade

At the beginning of your combat phase, Pay 3 life, choose one:
• Aatrox gets Double strike until the end of turn.
• Aatrox gets Lifelink until the end of turn.
• Aatrox must be blocked this combat.

World Ender — If Aatrox destroys an opponent creature in combat, untap Aatrox, there is an additional battle phase after this one.