This is a character I designed a year ago. Drew this when I drew the Dream thing, just didn't post.

Virus Chara is an insane human, who was created by the player installing a "Mod" (A Virus). She wasn't always crazy, but now is. Her world is gone, but frisk and maybe others survived. Their weapon is where the Virus mosly affects. (Blade can change shape)

Note: I know this concept existed before, but I don't know what happened to it.