I was rewatching the episode You're Level 100! and I caught some things I didn't mention in the previous chapter (because I didn't start rewatching the episode until after I published it)

He definitely looks a bit crazy in this photo, doesn't he? He still has them purple colored eyes, and he just looks uncharacteristically menacing (not that much, but the look is definitely unlike him)

Also before he gets hit by Darrel, his attack is blue, like his attacks normally are

Though after getting hurt and looking crazy like he did, his attacks are purple, the color of the one attack in the promo that I'm pretty sure comes K.O's shadow self

(images for reference here)

And it's not just the lighting, because the attack(s) are clearly purple here

I definitely think that person was onto something. No, seriously, I would've never realized this if they never would've pointed it out.