Metal Sonic is the second boss of Death Egg mk.II Zone and the sixth overall boss of Sonic the Hedgehog 4: Episode II. He is fought with Sonic the Hedgehog and Miles "Tails" Prower at the end of Death Egg mk.II Zone Act 1.
Metal Sonic once again challenges Sonic (along with Tails) to a race. Unlike the original, the race is on much more even ground. However there are several sections where doors will fall down, obstructing the pathway, these doors can be destroyed with use of the Homing Attack with 3 hits, or the Rolling Combo with one hit (note that Super Sonic destroys the doors in one hit with any attack). Metal Sonic is also lacking the abilities he had in the original race, relying solely of his speed to outrun Sonic.
As with the original race, the end contains a door (although this time it is electrified), if the player loses the race, Metal Sonic will run through the door before it closes, causing Sonic and Tails to crash into the door, losing the player a life. If the player wins, Sonic and Tails will run through the door before it closes, causing Metal Sonic to crash into it, defeated once again. It should be noted that if one uses the Rolling Combo or Super Sonic right from the start of the race, Metal Sonic is easily surpassed and any obstacles are instantly destroyed in one hit, thus one can use this trick to safely win the race if it proves difficult.
- This is the only boss in Sonic the Hedgehog 4: Episode II that has been reused from a previous game.