The Experiment No. 123 is an enemy in Crisis Core -Final Fantasy VII-. It looks just like Zack. This impostor is a tough foe to defeat — not to mention his sky high HP, he can also cast Regen on himself and even use a Phoenix Down for his own benefit. He can heal himself for roughly 24,000 points of HP every 5 seconds, and will use Exploder Blade or Energy to attack Zack. Cast a barrage of Graviga to deplete its HP, then attack the impostor with a series of Costly Punch. Timing does matter against this foe, so time your attack and defend correctly. Flare and Ultima are effective as they are area-effective magic. To protect from attack, have a Protect Ring equipped.