Snippets From A Forgotten Man

Sans is struck with sudden headaches without warning and has no idea how to heal them or where they came from. In the span of a month, he's too weak to get help and too dazed to wonder about the half of himself that feels missing. And the way he seems to be changing right under his own nose.
Cover - https://randomcolornice.deviantart.com/art/Sans-and-Gaster-647654553