In one of Eggman's recent plans, he discovered that there was a great gem that kept the entire island alive and magical as it was. He planned on stealing the gem to become even more powerful. Sonic tried to stop him, but broke the gem by accident, causing the entire universe to collapse. The dimensions have been separated.

Sonic had to travel through space-time to save his friends and the many versions of them in every dimension.

And soon it reached a dimension where everything was consumed by plants. He explored through the jungle for a while, but it was impossible not to get lost in such a place.

Then he found a creature. At first he didn't recognize it and he was even scared, but then he was able to recognize that it was Shadow, his rival, but as a totally different and unrecognizable creature. He was huge, had pointed claws and spikes, and looks more like a wild animal than a mobian.

Shadow turned to look at the blue hedgehog, and let out a growl from deep in his throat as he scurried through the bushes, hiding from Sonic's sight.