Phantom Zant is encountered twice, and is also seen early in the dungeon. It will start by throwing a ball of dark matter. The ball will then spawn large numbers of various Twilight Monsters including Shadow Keese, Shadow Deku Babas, and Shadow Beasts. After Link has killed all the spawned monsters, or the monsters have remained for a long time, Phantom Zant will continue to warp around the room (as he had been while Link was distracted by the monsters). At some point he will temporarily stop, then prepare to spawn more monsters. It is at this time Link can attack Phantom Zant the most efficiently. He will not have much time to do so, as Phantom Zant does not take long to create more monsters.
Each time after defeating Phantom Zant, Link will be able to obtain a Sol, which he must return to the entrance.
Phantom Zant is similar to Phantom Ganon in both name and in the sense that both are ghostly apparitions of their creators.