- You may be looking for Mobius, which was formerly known as Earth in the Pre-Super Genesis Wave Timeline, or Earthrock Trilobyte.
Earth in the year 20XX is an alternate reality which serves as the setting of the Mega Man series. A world where advanced robotics thrive, co-existing with humans, the most well-known hero of this world is the robot Mega Man, created by world renowned robotics engineer Dr. Light. It exists within its own Multiverse outside of the Multiverse that Sonic's own Prime Zone exists in. After Dr. Eggman and Dr. Wily pushed the second known Cosmic Reset Button and unleashed the second known Genesis Wave, it affected both this world and Sonic's world of Mobius and reset them each to the doctors' likings. This was later undone, restoring Earth 20XX to its previous condition except for a few small changes. Some time later, it would be caught up in the plot of Sigma-1, a villainous robot from its own future.
Dawn of the Robot Masters
Dr. Light created advanced robots known as the Robot Masters to help humanity, and in the process created his own robotic "children": Blues, Rock, and Roll. Unfortunately, Light's old partner Albert Wily grew jealous of his friend's successes, and determined to prove his own genius to the world by seizing Light's original Robot Masters from Light Labs. With the Robot Master running amok, Rock volunteered to be upgraded into a fighting robot who could stop them and bring Wily to justice. Thus was born Mega Man, a blue-armored hero who fought to protect his world from evil. (AMM)
The reality of Earth 20XX was rewritten by the second Genesis Wave employed by Dr. Eggman, who joined forces with Dr. Wily in a scheme to take over both their universes. This scheme moved Earth 20XX's timeline forward into the near future, which had seen Mega Man thwart several more attempts at world domination by Dr. Wily. Earth 20XX would then be invaded by the doctors' Roboticized Masters and Metal Sonic in their efforts to claim the Chaos Emeralds, leading Mega Man to pursue them to Eggman's home world of Mobius. Mega Man later returned to his world with Eggman's nemesis Sonic the Hedgehog in tow, only for Dr. Light to be abducted from Light Labs by Metal Sonic and Bass. A rescue party consisting of Mega Man, Sonic, Rush, Tails, and Proto Man subsequently departed from Light Labs to the Skull Egg Zone via a Warp Ring. They would be followed in time by Duo and the Light Robot Masters, who joined the battles taking place on and around the Wily Egg. Following the defeat of the doctors' scheme, Super Mega Man would use the power of Chaos Control to return his world to its former state. (MM: #24, #25, #27; SU: #51, #52, #53; StH: #248, #251)
Mega Man's Battle Continues
Earth 20XX's trials would continue, as the villainous supercomputer Ra Moon would then make its bid to conquer the planet. Afterwards, Mega Man would be forced to contend with another scheme of Dr. Wily's, while the anti-robot terrorist Xander Payne made a trip through time. (AMM)
100 Years Later
A century after the time of Mega Man, a scientist named Dr. Cain discovered Dr. Light's last and greatest creation hidden away in a capsule: an advanced robot known as X. Attempting to replicate X's design, Dr. Cain created a new generation of robots known as the Reploids, who possessed the ability to think and reason like humans. Unfortunately, many of the Reploids-whether of their own volition or due to the effects of a virus-became hostile to mankind, becoming known as the Mavericks. X would join the Maverick Hunters, a group dedicated to stopping this threat, alongside the mighty robot Zero. Together and with other allies, they faced off with the Mavericks and their evil leaders, Sigma and Vile. (MMX)
Mega Man's present and X's future would later collide and mingle with other worlds as well, thanks to the machinations of Sigma. After traveling to Mobius from his own time, Sigma would capture Dr. Wily from the past and force him to join Dr. Eggman in working on Sigma's plans to conquer both of their worlds. He would then send members of the enslaved Deadly Six to Wily's time to capture Mega Man. Subsequently, Sonic Man would be sent to Mega Man's time to place one of the Unity Engines central to Sigma's plan. This would result in battles between him and several of the Light Robot Masters, Quake Woman, and a handful of Wily's Robot Masters. At the same time, X and several other Maverick Hunters would set out from their time to try and find Sigma, and land in the Sonic Boom Zone in the course of their search. They would arrive in the past shortly after the Unity Engines began fusing it with the planet Mobius, which led to a battle between Sonic Man and M'egga Man that saw them both restored to normal. An alliance of heroes soon formed between the robots of 20XX and 21XX and the inhabitants of Mobius and the Boom Zone. Upon learning that the two merged worlds were in danger of being destroyed were they not separated, they set out to confront Sigma and put an end to his plans. (SU: #76, #77; SB: #8; StH: #273; MM: #50)
- Robot Masters
- Other Robots
In the year 20XX, this Earth's technology is comparable to-and in some cases compatible with-that of present day Mobius. One area in which the two differ noticeably is in the construction of the advanced Robot Masters; where robots on Mobius can often be recreated even if they are destroyed, the Robot Masters are virtually unsalvageable if their Integrated Circuits are destroyed.
Technology from the year 21XX is considerably more advanced than that of 20XX or Mobius, a fact that made Dr. Eggman covet its use. Its levels of advancement include the Reploids, robots possessed of free will, as well as the technology that allowed Sigma to manipulate the Genesis Portals and design the Unity and Master Engines.
- At the time the crossover occurred, this world had only recently entered the year 20XX just three issues prior.