The Black Shield (ブラックシールド Burakkushīrudo?) is Metal Sonic's special move in Sonic Adventure 2: Battle. When performing this technique, Metal Sonic protects himself from all offensive special attacks.
When performing Black Shield, Metal Sonic crosses his arms and bends his legs slightly upward while hovering in the air, where he forms an octahedral energy shield with black outlines around him. While it is up, the Black Shield rotates around him at high speed while his own body glows in a multitude of white, blue and purple colors.
While the Black Shield is active, Metal Sonic is invulnerable to damage from any special attack performed by his opponent, although he is still affected by immobilizing moves such as Time Stop. Additionally, while the Black Shield is being used, Metal Sonic cannot change direction, but he will maintain his momentum and even exceed his maximum speed when using it before landing on a Dash Panel.
The Black Shield can only be used in the games' two-player mode, as Metal Sonic is not playable anywhere else in the game. To use it in gameplay, the player must press and hold down the Action Button to raise the Black Shield. Unlike other special moves which require a set amount of Rings to be performed, the Black Shield can be used at any time.
In other media
The Black Shield first made an appearance in the Archie Comics' Sonic Universe #54 during the Sonic & Mega Man: Worlds Collide crossover event, where it was used by Metal Sonic v3.8. It is described as Metal Sonic's defense matrix and can block attacks.
The Black Shield appears in the Sonic the Hedgehog comic series published by IDW Publishing. It first appeared in Sonic the Hedgehog #29 where it was used by Metal Sonic to protect himself and Sonic from a giant fireball fired by Zavok.