Undertails || A Sonic X and Undertale Crossover

It's been 2 years since the Metarex War, and peace should be in Mobius, right? Unfortunately for the people of Mobius, that was not to be. Dr. Eggman, after adapting the Metarex designs to his own, created an unstoppable army. Not only that, but his own forces were consolidating power while he was fighting the Metarex, bolstering his might even further. In 2 years, nearly all of the planet was under his control. Tails, still broken from Cosmo's death, presents Sonic an extremely dangerous and risky idea: return to Earth and go back to the Thorndike's.

Whether Tails knows it or not, his decision to present this idea to Sonic just became the catalyst for something new for a forgotten race under the surface.