>>1376531
>The first instance of Dark Sonic never appeared in the comics either?
Technically, the comics did one first. The UK comics, simply titled "Sonic The Comic" had its own version of Super Sonic, named "Fleetaway Super Sonic" because Fleetaway Editions was the name of the publisher, that appeared when Sonic got too stressed or exposed to Chaos Energy.
I'm not sure on either of those conditions cause I never read it. That version of Super Sonic was batshit crazy and wanted to destroy everything. He became separated from Sonic for a while, but his story ended with him being fused back into the real Sonic. I don't know if Archie did a Dark Sonic, there was a robotized Sonic brainwashed by Robotnik and an evil clone of Super Sonic that might have been a reference to Fleetaway, but no Dark transformation that comes to mind aside from the Warehog in the Unleashed adaptation near the end of its run.
>It was just a one and done form that never gets mentioned again at any point as if it's not canon?
Pretty much, there's some fans thinking that Sonic X, or at least some version of the Metarex Arc where Dark Sonic is from, is turning canon due to Sonic X references in recent official material, including
the flower pot where Tails plants Cosmo's remains being seen.
Also, I just remembered Shadow has some dark transformations.
>Dark Shadow
Appears in Shadow '05
I'm glad I live in a timeline where I can call the game by that name since Shadow has TWO games now has a similar form in Sonic 06 called Chaos Boost. When Shadow does enough villainous acts in a stage, he temporarily becomes invincible, gets unlimited ammo, and can perform a giant explosion attack called Chaos Blast. He can also access this state even in Super Form during the final boss. The Sonic 06 transformation isn't really a dark transformation and isn't as powerful, so I won't talk about here.
>Doom Shadow
Appears in Shadow Generations, Shadow gains different abilities throughout the game as a plan by Black Doom to turn Shadow into either his new vessel or a perfect soldier for the Black Arms. Doom Morph in particular makes Shadow unrecognizable. Doom Wing also lets Shadow fly and become invincible at the cost of rings, just like a traditional Super Form. Of course, he loses all these once he beats Black Doom at the end.