Board Thread:General Discussion/@comment-26826023-20160201071856/@comment-27620479-20160406050231

I think, based on what we know about monster funerals, and well, Flowey's story, that Sans is going to Grillby's, to leave some of his essence there.

As for asking Papyrus, maybe it's an old habit.

Also, my vote is ketchup, because sans is a skeleton, determination isn't something you can just pop down and buy in a shop, there is no sign that Alphys keeps any amount in her lab, and why would she anyway?