What’s this I hear about him being part alien?

Shadow the Hedgehog, the 2005 game starring Shadow as the sole playable character, is a complicated web of stories to unpack. The platformer is choice-based, allowing you to see different stories unfold based on which missions you complete in each level. If I kill a bunch of bad guys, I can see Shadow go down a heroic path. If I sabotage Sonic and friends, I can watch him revert to his villainous ways. All of these are portrayed as “what if” scenarios, but the game does tell us a lot more about how Shadow came to be.

In between all the alternate histories, it’s revealed that while creating Shadow, Robotnik sought the help of an alien race called the Black Arms. These invaders occupy a comet that passes over Earth every 50 years or so, and plan to return to the planet in a few decades to impose themselves on humanity. Robotnik made a deal with the aliens to further his research, offering to have Shadow help with the invasion in exchange for the DNA of Black Doom, the aliens’ leader. Shadow’s memories are still gone, but Robotnik left a video message from before the raid on the Ark with instructions for Shadow to use the Eclipse Cannon to destroy the Black Arms’ comet and save the world. Shadow faces Black Doom in a final fight, then blows up the comet from orbit. He then makes the decision to leave his past behind and determine his own future…but not before Eggman confirms that he is, in fact, the original Ultimate Life Form, whom he rescued after the events of Sonic Adventure 2. Wildly enough, this confirmation only comes if you take over eight minutes to complete the final boss battle, so plenty of players never hear this voice line from Eggman.