Underground Galaxy

The Sonic Underground Galaxy is supposedly the Galaxy where the continuity of the TV series Sonic Underground takes place. Run the Hedgehog briefly visited this galaxy, but ended up destroying Earth, killing everyone on it save for himself, and three women he saved.

Inhabitants

 * Sonic Headchog - The Underground variant of Sonic the Hedgehog. Accepted Run's challenge to race around the planet.
 * Amy Rose The depressed Demon Queen - A hedgehog who witnessed Run race Sonic and was saved from the planetary explosion by Run, being taken to the Love-Making Galaxy to become impregnated by him.
 * Sally Acorn - A chipmink who witnessed Run race Sonic and was saved from the planetary explosion by Run, being taken to the Love-Making Galaxy to become impregnated by him.
 * Venus the Hedgehog - Venus arrived just before Run blew up the Earth and was saved along side Amy and Sally to be taken to the Love-Making Galaxy.

Planets

 * Earth - The planet was destroyed by Run during his race with Sonic. Every inhabitant was killed save for Amy, Sally and Venus.