I wonder if Sans is a result of time and space manipulation and his original name was-

Papyrus’ body isn’t real.
So what is a Sans and why does he have so many similarities with Lancer and a picture of Ralsei, Susie, and Kris? The kind of people only someone like Lancer would be close to when Sans has barely seen the three for at least three days.
What if the strange machine in Sans’ basement was the machine we created in chapter 1. Which again, is an object only Susie, Kris, Ralsei, and LANCER would care for.

The one weakness Sans has that only King and Jevil have out of the powerful Darkners is exhausting themselves from using their own attacks. Which is a weakness Lancer would inherit from his own father.

Aka, Lancer is befriending Kris’ mom out of all people.