These are the second type of Phantom that Link will encounter within the Temple of the Ocean King. They move at a significantly faster speed than the standard Blue Phantom and are thus, much more dangerous. If a Swift Phantom strikes Link, he will lose 30 seconds of Sand of Hours from his Phantom Hourglass.
Swift Phantoms are first encountered during Link's fourth trip to the Temple of the Ocean King, after completing the Ghost Ship. They take the place of some of the Blue Phantoms on the lower floors and appear as regular enemies in some of the later floors. Some of these Swift Phantoms are carrying, or can pickup, Small Keys or Jewels. In order to get a Swift Phantom to drop an item, Link can shoot the Phantom in its backside with an Arrow, temporarily stunning the enemy. During his final trek through the Temple of the Ocean King, Link has acquired the Phantom Sword and can defeat a Swift Phantom with a sword slash to its back.