Phantom Guard

The Phantom Guard is an enemy in The Legend of Zelda: Phantom Hourglass that stalks Link around the Temple of the Ocean King. They look like Darknuts, but when they hit Link, thirty seconds are taken off the timer and Link loses one heart. In addition, they are invincible until the near the end of the game. There are "safe zones," however, that the Phantom Guards cannot enter. There are three varieties of Phantom Guards: the blue ones are the slowest, the red ones are faster and can pick up keys and Force Gems, and the gold ones can instantly teleport to wherever Link is, but move slowly on foot.

After the fourth dungeon is cleared, it is revealed that the Phantom Guards are actually alter egos of Bellum. The Phantom Guards are also playable in Phantom Hourglass's multiplayer mode. Here, players will take turn playing offense (Link) and defense (Phantom Guards), trying to collect Force Gems.

Other types of Phantoms
A Swift Phantom is nothing more than a regular Phantom that runs faster and can pick up dropped items. As long as you can run fast, you should do fine with these guys. A Slow Phantom Guard is just an slower version of a regular or the swift Phantom but it can teleport instantly where Link is if any other Phantom or Phantom eyes see Link.
 * Swift Phantom Guard
 * Slow Phantom Guard