|Fast Facts on Phantom Egg|
The Phantom Egg is the twelfth major boss fought in Sonic Mania, encountered at the end of Titanic Monarch Zone Act 2. It is a fearsome mechanical bodysuit worn by Dr. Eggman and powered by the mysterious Phantom Ruby, and is the game's final boss unless the player is playing as Sonic and has collected all seven Chaos Emeralds.
When the boss begins, the timer on the HUD is reset to zero, and the Phantom Egg is surrounded by an impenetrable red shield that deflects all attacks, including those from super characters. In this state, the doctor hops around the room, occasionally firing the four missiles on his back at the heroes, leaving visible crosshairs where they will strike. Eventually the scientist lands, electrifies the appendages that suspend the machine in the air, and removes the barrier; the appendages become de-energized shortly before the shield goes back up, buying the heroes a chance to land a hit or two before it becomes invincible again (alternately, super characters or those with Lightning Shields can attack the doctor for the duration of the time his shield is down). Occasionally, Eggman will produce two phantom hands that will drift towards the player until he grabs them, warping them to another room temporarily to be attacked by one of the four subordinate Hard-Boiled Heavies, all of which have been transformed into new "Phantom" forms. Phantom Gunner attacks with rockets fired from the background, Phantom Shinobi bounces or charges around the room as a giant shuriken and occasionally fires his outer spiked segments off temporarily before summoning them back to himself, Phantom Magician has three enormous cups that spin around each other like a shell game before revealing herself (the other two fire enormous lasers), and Phantom Rider will place the hero on an autoscrolling obstacle course that continues until she hits a wall. It is not possible to destroy any of the Hard-Boiled Heavies in these upgraded forms; the player simply has to survive their attacks for a short period, after which they are eventually warped back to Eggman and the fight resumes.
Dealing four hits will destroy one of the Phantom Egg's appendages and make it easier to strike the doctor; the eighth hit destroys the second appendage (allowing Eggman to float in midair at times instead of bouncing), the twelfth hit blows the third appendage off, and landing the sixteenth and final hit destroys the machine outright. If the player is Sonic with all seven Chaos Emeralds, the Emeralds will interact with the Ruby and warp Sonic, Eggman, and the Heavy King to Egg Reverie Zone; otherwise the Phantom Egg cracks and drops a tantruming doctor on the ground, prompting the player to flee with the other heroes in a rocket car nearby as Titanic Monarch Zone goes up in flames.