Board Thread:General Discussion/@comment-27907368-20160514064034/@comment-26887879-20160515101543

Aicilespear wrote: PancryPancreas5 wrote: He knows these things buy looking at Frisk's expression. You can skip the Genocide part, because I don't think it's really convincing.

Going back to Papyrus, Sans will tell you to watch out for blue attacks when you battle Papyrus. However, if you have killed Papyrus, then reload your save point to before confronting Sans and going to the town (or just make a reset completely), he will tell you to not fight Papyrus at all. If you haven't killed anyone, he'll tell you to remember blue attacks. If you have killed a single enemy before, he'll tell you not to fight Papyrus. Also, Sans isn't the only one who changes his dialogue after resets/reloads...