The Phantom King, now bigger and stronger than his previous form, still retains the same red, gold, and white color scheme he sported before. Losing his legs, he has gained purple, square-like legs that dangle from his bottom. His shoulders and collars have also become more pronounced and the crown on his chest has become red, though at the cost of his cape. His circular arms are coated with spikes. His bronze-colored armor-plating has also become yellow and more pronounced, covering most of his body. The Heavy King, in this new form, is at the size of the Klepto Mobile.
When Sonic and Eggman were sent to Egg Reverie Zone with the Phantom Ruby, the Phantom King swiped the Phantom Ruby and used it to power himself. However, the Phantom King met resistance when Eggman (with the Klepto Mobile) and Super Sonic fought him separately for ownership of the Phantom Ruby. At the end of the conflict, the Heavy King was seemingly destroyed by Super Sonic, failing at his goal at harnessing the Phantom Ruby.
Powers and abilities
In his new form, the Phantom King is powerful enough to bypass a Super State user's invulnerability with his most powerful attacks. His energy manipulation abilities have also been increased to the point where he is able to manifest and control energy spheres without his scepter.
The Phantom King appears as one of the two final bosses of Sonic Mania (the other being the Klepto Mobile). During the battle, the Phantom King will surround himself with impenetrable energy spheres that can make the player lose ten rings upon contact when fired at the playable character. The player must find an opening or wait until he no longer has a shield to strike. Hit Heavy King eight times and he will be destroyed.