Sans and.........Papyrus?(SO!Dusttale)

Description: after many genocide routes, sans decided to go worst case scenario; he used gaster's final creation (CS Save), which resulted him with having high HP and LV. however, this creation was unstable and has traces of gaster within. so not only did sans lose his mind, some of his mind is now gaster's mind. the hole where his mouth used to be was caused by undyne, an attempt to kill sans. papyrus is "along for the ride" cuz sans wants papyrus to finally understand, that kindness isn't the answer