Mecha Sally (AKA Robot Number Three-Three-Nine-Zero) is Sally Acorn roboticized, she first appeared when Robotnik roboticizes her and she captures the freedom fighters. she gets de-roboticized
Weaponized Mecha Sally

Mecha Sally

Mecha Sally later appears after Sally attempted to stop the Death Egg Roboticizer, getting herself Roboticized but saving the world, she then married Metal Sonic and attacked Sonic. She was later upgraded with a new apperance and abilities using power ringsm due to her apperance being modified it is unlikely she can be de-roboticized.

Sally is later revealed to be the Traitor and the one who will destroy the world.