The Phantom Magician has the exact same appearance as her normal form.
In Sonic Mania, during their climactic fight with the Phantom Egg, Sonic, Tails and Knuckles got transported to a different room where they fought the Heavy Magician-turned-Phantom Magician. Their fight was a brief one though, as Sonic and co. were returned to their fight with the Phantom Egg before the Phantom Magician managed to defeat them.
The Heavy Magician soon after became the Phantom Magician again. When Sonic, Tails, Knuckles, Mighty and Ray fought the Phantom Egg, the group of heroes got transported to a different room where they faced the Phantom Magician. Like before however, the Phantom Magician missed the chance to eliminate Sonic and co. when they got pulled back into the fight with the Phantom Egg.
Powers and abilities
The Phantom Magician is capable of flight and commands three giant cups which she uses to play shell games with. These cups are able to project giant lasers from their openings.
The Phantom Magician segment is the third section the player will be transported to. Here, the player is forced into playing the shell game: there are three bowls, one in the middle that the player must pay attention to while the bowls will be shuffled. When the bowls are done shuffling, two of them will blast at the player, but the bowl that the player should have paid attention to at the beginning of the segment will be the bowl that will not blast at the player. The Phantom Magician will appear in the middle before moving up with the bowls and ending the segment.
It was never revealed if the Phantom Magician ever turned back into the Heavy Magician during the opening of Encore Mode in Sonic Mania Plus due to their appearance being identical.