Dark Sonic is a cool concept and I'm tired of pretending he isn't. It's like a super form but based off of negative emotions, hence why Garland here's flipping the bird!

I like the idea it's just raw power that overrides any sort of strategy in the user, making them a completely dangerous loose cannon who could easily hurt themself as much as their enemy. And since it's built off of negative emotions, and since Garland has enough trauma to need a busload of therapists... good luck!