Resistance

I imagine the receiving end of that look wonders whether whatever it'd done was worth it.  Sonic angry + dark, ominous glow + the chaos Emeralds = you're screwed.
I love the details, like the lack of gloves and fading gold.  The desolate background and Sonic's pose makes me think something earlier happened that destroyed whatever was there, that Super wasn't enough--and then maybe something made him snap and go Dark.