Phantomtail

The Phantomtail (テイルミラージュ) is an Emblem Heartless Boss exclusive to Kingdom Hearts 358/2 Days.

Kingdom Hearts 358/2 Days
These large aerial Heartless can't be harmed by blows to the head, instead warping to a remote location on impact. ''They won't warp, however, if you attack their wings or tail, so focus attacks there. Go in equipped for aerial combat.''

Kingdom Hearts 358/2 Days

 * Neverland

Kingdom Hearts 358/2 Days
It appeared before Captain Hook and Mr. Smee in Neverland while the duo dug for buried treasure, the pirates fleeing and leaving Roxas to duel the monster.

Strategy
At the start of the battle, Lock-On to the Phantomtail's wings or tail as it hovers above you. As this is an aerial battle, you must jump to the Heartless' level before you can begin your attack. Use caution, as the Boss will eventually proceed to summon homing balls of blue energy to damage you. From this point forward, the Heartless will warp around the battlefield, making attacks difficult to land.

You must also be careful not to get too close to the Phantomtail, as it will stab you with its talons in an attempt to knock you away. Another attack in this Heartless Boss's arsenal involves it spiraling into you, dealing impact damage. The Phantomtail will also flip in the air, damaging those in its way. So long as you heal periodically, utilize your Limit Break, and attack whenever possible while at the same time dodge the beast's attacks to the best of your ability, you should be able to tackle the Phantomtail in a matter of minutes. If you wish to use Magic in this battle, use the when the Heartless is stationary. Attempt a spell while the beast warps to a new location, and your spell is guaranteed to miss.