“All living things, kneel before your master!” —Neo Metal Sonic, Sonic Heroes
Neo Metal Sonic is a transformation that appears in the Sonic the Hedgehog series. He is one of Metal Sonic’s transformations, which he once used to disguise himself as Dr. Eggman and copy the data of his foes in order to make himself more powerful.
Neo Metal Sonic in Sonic Heroes
Prior to Sonic Heroes, Metal Sonic assumed this form as he sought to defeat Sonic on his own and conquer the world himself, as he held the “key to destroy the world.” To this end, he betrayed Dr. Eggman, took control of the Eggman Empire and began seeking out the data he needed for him to transform into Metal Overlord. To achieve this, Neo Metal needed to copy the lifeform data of other beings. Using his shapeshifting abilities to pass as the real Sonic, Neo Metal would also kidnap Froggy and Chocola in order to obtain their data on Chaos as well.
When Team Sonic, Team Rose, Team Dark, and Team Chaotix begin their adventures, Neo Metal Sonic would cross paths with the groups on various occasions in the guise of Dr. Eggman and get the lifeform data he needed from them. By the time Team Dark and Team Sonic defeated the Egg Albatross, Neo Metal Sonic had successfully copied Shadow’s data and that of all the teams, and when Team Rose defeated Neo Metal Sonic in the Egg Emperor, he had copied Chaos’ data as well, making him release Froggy and Chocola from captivity.
With all the data he needed, Neo Metal revealed himself to the heroes and destroyed the Final Fortress’ tower before using debris to transform into Metal Madness, and later Metal Overlord. However, he was later defeated by Team Sonic and reverted to Neo Metal Sonic, and then back to his original form with Sonic promising a rematch at any time.
Neo Metal Sonic in Sonic Rivals
Neo Metal Sonic makes an appearance on the 150th collectible card in the game.
Neo Metal Sonic in Sonic Dash
Neo Metal Sonic is set to appear as a playable character.
Neo Metal Sonic in Sonic Forces: Speed Battle
Neo Metal Sonic is set to appear as a playable character.
Neo Metal Sonic in Sonic the Hedgehog (Minecraft)
In the Sonic the Hedgehog pack for Minecraft, Neo Metal Sonic can be seen in one of the paintings within the texture pack.
Neo Metal Sonic in Sonic Speed Simulator
In Sonic Speed Simulator, as stated by Sonic, him and Dr. Eggman were working together during the “Super Sonic: Powering Up” Event. Once the player finishes the event, the Neo Metal Sonic Boss Battle is unlocked, where the player can take on Neo Metal Sonic as Super Sonic. In this scenario, Eggman has helped Neo Metal Sonic power up to his “peak” form using the Chaos Emeralds, making him roughly three times larger in size than normal.
Neo Metal Sonic later appeared as a playable character during the “Metal Overlord” Event. In gameplay, he has the ability to fly that replaces the Air Boost. He can fly for as long as he wants until the Energy gauge is empty.
Neo Metal Sonic in Sonic Frontiers
Sage mentions Neo Metal while telling Dr. Eggman that he and Sonic worked together many times to stop threats, such as the former and the Space Colony ARK.
Neo Metal Sonic in Shadow Generations
Although Neo Metal Sonic himself doesn’t appear in game, his Metal Overlord form acts as one of the bosses that Shadow ends up fighting.
Source: Neo Metal Sonic—Sonic Wiki Zone