What seems to be more obscure is what the back of Goner Kid's head looks like.
Two things of note: the back of Goner Kid's head has two lines on it, and the (presumably) horns on Goner Kid's head are drawn differently than Monster Kid's horns. It's almost like the horns were drawn differently specifically so those two lines could be visible.
So, some people have said they think those lines on Goner Kid's Head are eyes. I think that's kind of true, but, while working with Goner Kid's sprites for a separate reason, I realized something.
They aren't eyes; they're pupils.
As in, Goner Kid's missing pupils are on the back of their head.
I edited the pupils onto Goner Kid's eyes, and they're an exact match
I don't know if I'm the first one to point this out on Tumblr, though I do know that people over on Twitter were surprised when I realized this.
For the sake of comparison, for an image of the sprites together.
Original scale of the Goner Kid edit for anyone who wants to use it for whatever reason.
OMG HI AGAin people im sorry that this is just like another line up of undertale characters lmao
I made this one a while ago because I was not happy with the sans I drew last time but never posted it so uhh here lolsies
ALSO I APOLOGIZE TO THE ASGORE COMMUNITY FOR NOT DRAWING MORE OF HIM LMAO I will one day I promise I just was not in the mood for armor at the time lolsies