Turbo Mecha Sonic

Mecha Sonic (originally known as Metal Sonic) is a robot created by Dr. Eggman for the sole purpose of destroying Sonic. He serves as the primary antagonist for the first saga of Super Mario Bros. Z. After Metal Sonic was created, he fought Sonic in their first battle, and lost. However, he returned faster and more powerful than ever, but was still beaten. Meanwhile, Metal Sonic sneaked into the Death Egg, combined with all of the other Sonic robots, and transformed into the almighty Mecha Sonic. As Dr. Eggman entered and threatened to deactivate Mecha Sonic for his disobedience, Mecha Sonic causes the Death Egg to crash into Mobius with Eggman on it. After destroying the Death Egg, Mecha Sonic decided to search for the 7 Chaos Emeralds while killing Sonic's friends in the process. He kills Tails, Amy, Knuckles, Cream, Cheese, and presumably Rouge and Omega. Mecha Sonic collected six Chaos Emeralds while Sonic had the seventh emerald. He found Sonic, easily defeated him, and got the last Chaos Emerald. Before Mecha Sonic can transform into his ultimate form, Shadow used Chaos Control to send the Chaos Emeralds to a different dimension. Before Sonic and Shadow could fight the robotic tyrant, Mecha Sonic used Chaos Control that he had absorbed some of their power to teleport to where the Chaos Emeralds were, thus leaving Sonic and Shadow behind with no way of pursuing him.

The place where the Chaos Emeralds were transported to was the Mushroom Kingdom. Just as a Goomba took the blue Emerald, Mecha Sonic appeared. He told the frightened Goomba to give him the emerald, but the Goomba asked him what's a Chaos Emerald. So Mecha Sonic charges up his attack, kills the Goomba, and takes the blue Chaos Emerald. He then continues his search for the other six emeralds. Later, he finds Yoshi with the red Chaos Emerald, and seriously injures him, while taking the red emerald back. As Mecha Sonic was about to kill the wounded Yoshi, he surprisingly saw Sonic and Shadow, with Mario and Luigi at their side, who managed to get to the Mushroom Kingdom as well. The menacing robot then left before Sonic and the others could even figure out he was there.

Sometime later, he finds that the other two Chaos Emeralds are on Yoshi's Island and speeds directly to the island. As Sonic, Shadow, Mario, Luigi, and Yoshi are fighting the Koopa Bros. and the Axem Rangers X, Mecha Sonic arrives, and easily defeats the Koopa Bros., destroys the Axem Rangers' ship: the Blade, and takes the two emeralds. While Mecha Sonic was taunting the heroes, Axem Red red with his scouter that Mecha Sonic's power level is over 9,000. Red orders Axem Yellow to destroy Mecha Sonic, but as Yellow swung with his axe, it fell apart. Mecha Sonic then uses the four Chaos Emeralds to transform into Semi Super Mecha Sonic. He then fights the Axem Rangers and defeats them all. After he destroyed the Axem Rangers, he fought the heroes. The battle resulted in Mecha Sonic knocking Mario unconscious and pushing the heroes back. Semi Super Mecha Sonic taunts Sonic, and decides to destroy Yoshi’s Island. Before Sonic could even stop him, Semi Super Mecha Sonic teleports into the sky, and creates a very large energy bomb, large enough to destroy the entire island. As the heroes and the Yoshi tribe start to think that they are done for, Luigi revives Mario with a Life Mushroom that Princess Peach gave to him before he and the heroes departed for Yoshi’s Island. After being revived, Mario finds a Power Star, and comes up with a plan: combine the Starman’s power with himself and Sonic. The Power Star gave Mario the power to be invincible while Sonic gained his super form. Together, they run into Semi Super Mecha Sonic, making him lose his Semi Super form and the four Chaos Emeralds. Super Sonic catches them, and starts to finish off Mecha Sonic. However, before Super Sonic could do so, he reverts back to his normal form and falls. Mecha Sonic then sends the energy bomb hurling towards the island. As Sonic and Mario were falling, Sonic tosses the purple Chaos Emerald to Shadow. Then Shadow used Chaos Control to teleport himself, the other heroes, and the whole Yoshi tribe away from the doomed island. The Koopa Bros., who were still unconscious, didn’t make it out alive and perished in the explosion. Despite having Yoshi’s Island destroyed, Mecha Sonic was still mad about losing the Chaos Emeralds he had, and starts to hunt the heroes down, making them #1 on his hit list.

The next day, Mecha Sonic confronts Mario and Sonic in the Pipe Maze, and defeats them without hesitation. Before the angered Mecha Sonic could kill Sonic, Mario jumps and lands on top of the vengeful robot, picks up Sonic, and jumps into a warp pipe, and Mecha Sonic follows them. The world they warped to was the Minus World, a prison world saturated with “negative energy,” causing the world and everyone in it to enter an 8-bit form. 8-bit Mecha Sonic finds 8-bit Mario and Sonic with their other friends, Kolorado and Goombella, with the silver Chaos Emerald, and fights the two heroes. 8-bit Mecha Sonic lacks many of the abilities he can use outside of the Minus World, although this may be a result of the Minus World itself rather than a side effect of his 8-bit form. Despite this handicap, 8-bit Mecha Sonic was still strong enough to beat Sonic and Cape Mario (also in 8-bit forms). He takes the Chaos Emerald and tried to use Chaos Control, but he realizes it won't work. So he decides to finish off Sonic, Mario, Goombella, and Kolorado. However, Shadow appeared out of nowhere, and took the Emerald, and tried to use Chaos Control as well, but still no avail. As the heroes fight Mecha Sonic, Luigi enters the Minus World and crash lands onto Kolorado, causing him to drop his stopwatch. The stopwatch unexpectedly turned to Minus World, as well the fighters, to their normal forms. Mario is then contacted by Professor E. Gadd, who tells the heroes that they can finally get out the negative world or otherwise they will all be trapped there for all eternity. The heores race to the exit with Mecha Sonic in hot pursuit. They all escape the Minus World, and before the could be incinerated, Shadow used Chaos Control to teleport away from the Pipe Maze.

Super Mario Bros. Z’s creator, Alvin Earthworm, has confirmed that Mecha Sonic will get all 7 Chaos Emeralds.