Board Thread:Speculation, Theories, and Rumors/@comment-34518800-20150509005546/@comment-25819077-20150518144929

No. That was a 3-D version of Mecha Sonic from StH 2.

Also, while Metal Shadow would be awesome, I can't think of a legit reason for sonic team to put him in a game, especially when Shadow's not Eggman's outright enemy. Then again, Sonic team does a lot of things without a legit reason, so I wouldn't be all that surprised.