Dark Metal Sonic is Metal Sonic transformation in Sonic and the Twilight Darkness. Created under the influence of Darkness.
Dark Metal Sonic is the only one that is no different except for the Dark Aura and the dark counterparts of its powers.
When the fog of darkness was approaching, Metal Sonic was taken over by this fog. Metallic Sonic later fought Sonic in the Eggman Mansion.
In the normal end of the game, Metal Sonic returns to its form. In the real end Metal Sonic survived the battle in the mansion and through the very great power of dark he was able to speak and control the power of darkness. He used Crystal Move, which caused that the whole Earth was covered with Crystal, and Sonic he had to defeat him.
After the fight Metal Sonic falls to Lawa telling his enemy to help, but Sonic said he does not help enemies Metal Sonic was burned by lava, and the whole Earth was again normal.