I consider these the best designs for swapfell sans and papyrus. Underswap already had a sense of weirdness that sets it apart from Undertale. So, I think the blend of purple is a lot better than red. I don't really like the better known design of swapfell sans since him being that short in those clothes just feels really off. And even though I like the other purple design for swapfell sans, I like this one a lot more. Fantastic work.