This transformation exists primarily or exclusively within the Post-Super Genesis Wave continuity. Information in this article may not be canonical to the storyline of the games or any other Sonic continuity.
Perfect Dark Gaia is a transformation that appears in the Sonic the Hedgehog comic series and its spin-offs published by Archie Comics. It the true form of Dark Gaia, achieved when the beast reaches full maturity.
Every ten thousand year since primordial times, Dark Gaia has achieved this form when emerging to destroy Sonic's World, only to engage Light Gaia in a fight that lasts for centuries. At the end, Light Gaia defeats Perfect Dark Gaia and seals it and himself in the planet's core where they rest until their next battle.
Shattered World Crisis
When the world broke apart from the excess energy of the Super Genesis Wave, Dark Gaia was unable to reach maturity due to its premature awakening. Instead, its power was scattered across the broken planet. However, Dr. Eggman would create Eggman Land and the Summoning Spire to gather and harness it as a fuel source. Eventually, the spire collected enough energy for Dark Gaia to assume an incomplete physical form, destroying Eggman Land when emerging from the planet's core. After drawing in its remaining power to fully mature into Perfect Dark Gaia, Dark Gaia was forced to fight the combined forces of Super Sonic and the Gaia Colossus, who were able to defeat Perfect Dark Gaia and seal in the planet's core again after an epic battle.
Powers and abilities
Being at the peak of its strength and capabilities due to having regained its full power, Perfect Dark Gaia can generate a force-field via its serpent-like growths that even Super Sonic could not penetrate. Perfect Dark Gaia possesses as well immense endurance, and impressive combat skills; it could withstand most of the attacks from both Super Sonic and the Gaia Colossus, and fight both of them at the same time. It also has great strength, enough to completely immobilize the Gaia Colossus in its grip and deal hefty blows with its sharp claws. It can also fire an immense energy beam from its central eye which packs enough power to bypass Super Sonic's nigh-invulnerability.
The only known weak spot on Perfect Dark Gaia's is its eyes, which can inflict a great deal of pain on it if hit.
Perfect Dark Gaia originates from the game Sonic Unleashed, where it serves as the game'a final boss.