AntiSora

The AntiSora (アンチソラ) is a Pureblood Heartless that is found in Kingdom Hearts. It is one of the bosses at Neverland and a more powerful version of the Shadow Sora also seen in that world.

Kingdom Hearts
Sora encounters Riku on Captain Hook's ship, where he reveals that he now has control over the Heartless. To prove it, he creates a Heartless replica of Sora before their eyes, and it throws Sora into the ship's brig. As Sora fights his way back to the ship's deck, he encounters many of these Shadow Sora's, which only Sora can defeat. However, they have no weapons and often vanish before Sora even attacks them. Once Sora reaches the Captain's Cabin, Riku creates a more complete replica of Sora, this one able to wield a shadowy Keyblade. Sora eventually defeats it, and it fades back into darkness.

Strategy
The spells recommended to set to shortcuts are Aero, Cure, and either Thunder or Stop. Thunder allows Sora to attack AntiSora wherever it may be, while Stop can freeze AntiSora for a short period of time. Unlike Sora, AntiSora is unable to use magic, but can instead transform into a flat shadow and move about in that state. It can deal a lot of damage if Sora is caught when it leaps back out of the ground. So be sure to keep Sora in motion to help reduce the damage when he reappears. After half of its HP is depleted, AntiSora creates replicas of itself to distract you, so use the Scan ability to help speed things up a little bit. Be sure to keep your HP within a tolerable level - heal when necessary.

Trivia

 * AntiSora is one of only eight enemies who do not have entries in Jiminy's Journal. The others are Bit Sniper, the Cave of Wonders Guardian, Chernabog, the Crank Tower, Glut, Shadow Sora, and World of Chaos.