THIS IS A BIG “WHAT IF?” SCENARIO IT NEVER HAPPENED IN THE MAIN STORYLINE…
Sans wouldn’t let it slide if someone hurt Little Pup. Papyrus, on the other hand, would probably nurse Little Pup instead (in my mind, he doesn’t seem to be the sorta guy who acts out on revenge).
So, what if–godforbid–Little Pup got killed?
(SAD PIC UNDER THE CUT.)