It has two stripes on its shirt. Regardless of which shirt you pick, it has two stripes.
Kris only has one stripe on their shirt. Ever.
The vessel pieces are called “goner” pieces.
..... Goner Frisk?
Theory crap under the cut
OK but seriously, it makes sense for Frisk to be a Goner in Deltarune. Our Hero (Villain?) is Kris, a teenage character who seems to be taking Chara’s place as the soulless entity that you can’t control. Kris is in the overworld with monsterkind, and is the only human in town.
Since there’s no need for the Barrier Underground to be broken, a time anomaly has been caused, and the unnecessary parties have been “deleted” from the timeline. But just like hitting Delete without using Shift on your computer, a Goner is not completely wiped from the universe - they’re only in the universe’s Recycle Bin. That’s why we see Goners during Undertale’s fun/Fun timelines, is because they’re “gone,” but not forgotten by the universe. There’s a slight chance we’re dealing with Goner Frisk here. And if not, well, it’s still a goner-human with a different
Whether or not you get to use this vessel and play as the Goner wandering the Void (Recycle Bin, so to speak), we don’t know yet. But if we do, that’d be pretty neat. If the Goner is Frisk, that’d be SUPER NEAT. It’d be awesome if we have some kind of Gaster tie-in, but except for a few weird noises, we don’t know if the guy even exists here, even as a part of the Recycle Bin Crew. And just like Asriel in Undertale, if our Goner Human meets Susie or Asriel, they’re going to have us mistaken at first because the Goner once again looks remarkably like Kris and Frisk.
I dunno, this is just my theory. I fully accept the possibility of being super hecking wrong in the future, when more chapters are added to the universe. Enjoy my bullcrap rambling.