Genesis Wave

The Genesis Wave is a phenomenon created using the energies of a Chaos Emerald to rewrite reality. The technology, centered around the Cosmic Reset Button aboard the Death Egg Mark 2 and later the Wily Egg, was developed by Dr. Eggman, and has been used by him both alone and in alliance with Dr. Wily to alter Mobius on two occasions and Earth 20XX once.

First Wave: Clean Sweep
Dr. Eggman first conceived of the Genesis Wave after coming to the realization that Sonic was apparently the embodiment of the Chaos Force, making him an unpredictable element that would always upset any situation. After completing and launching the Death Egg Mark 2, he unleashed the wave as part of Operation: Clean Sweep. The resulting reality was different in a number of ways from how it had previously been, including a timeline in which Sonic, the Knothole Freedom Fighters-minus Bunnie Rabbot-D'Coolette-and Eggman hadn't met until the "new" present. Bunnie herself was also a prisoner of Eggman in this new reality, and cousin to Cream the Rabbit, whom in the unaltered Mobius she had been unrelated to. ({StH: #210, #225, #226, FCBD 2012)

Effects
For the most part, the Genesis Wave has been shown to drastically alter reality on whatever world(s) it effects, often leaving the affected inhabitants with amnesia or senses of deja vu. However, the wave does have some limitations as explained by Eggman and Wily: for one thing, it is apparently incapable of outright erasing individuals from existence.

Background Information

 * The Genesis Wave obviously refers to the Sega Genesis game system, on which the Sonic the Hedgehog games debuted. Indeed, its first usage altered Mobius' realty so as to make it more similar to the earliest Sonic the Hedgehog games, though with a few prominent elements from the Sonic the Hedgehog animated series.