- For other bosses with the same name, see Mecha Sonic. For the Sonic Mania Badnik based on this boss, see Silver Sonic (Sonic Mania).
Mecha Sonic (メカソニック), known as Silver Sonic outside of Japan, is the sixth and potentially final boss of the 8-bit versions of Sonic the Hedgehog 2, fought at the end of Scrambled Egg Zone. As the 8-bit versions of Sonic 2 were released before either the 16-bit Sonic 2 or Sonic CD, this boss fight marked the very first time a mechanical copy of Sonic was seen in any Sonic game.
Scrambled Egg's version of the robot is the same size as Sonic and mimics all of his abilities, even having a Spin Dash attack, despite the fact that Sonic lacks the Spin Dash in this game. When Sonic and Mecha Sonic's Spin Attacks collide, both characters bounce off each other, unlike the 16-bit iterations where Sonic takes a hit. This makes for a fast and hectic, if easier, battle. Mecha Sonic is also equipped with jet boots that enable it to hover, and a sharp scissors-type tentacle, which sometimes protrudes from its torso when standing still; the tentacle is extremely unlikely to damage Sonic unless he is standing right next to the robot.
The robot takes 8 hits to kill; if Sonic has successfully collected the 5 available Chaos Emeralds by this point, Mecha Sonic will release the sixth and final gem upon defeat. Only when Sonic has collected all six Emeralds can he proceed to Crystal Egg Zone and rescue Tails, thus triggering the good ending. If Sonic doesn't have enough Emeralds, the game will end and display the bad ending.