This is a crossover idea I had in my mind; basically, Sonic and a few of his friends decide to travel to the Great Valley.
However, after pressing a button, a system malfunction brought themselves, their houses along with Tails' workshop and inventions including his plane that was equipped with a dimension traveling device to the Great Valley.
This story takes place five years after the dinosaurs migrated to the Great Valley; so, that makes the kids 10 years old.
Little did they know, that Eggman had stolen the plans from Tails and had equipped his egg shaped flying machine with the same thing; and yet, his fortress also appeared in the Great Valley; but, it landed on the border near the Mysterious Beyond.
I have three chapters posted on fanfiction.net.
Here's the link below.
https://www.fanfiction.net/s/12376288/1/Adv...and-Before-Time
