So the idea came to me one time, and I just randomly thought of an AU where Papyrus was Undyne

Here's just a list of every swapped character (note: sans and pap are NOT related in this au)

Pap - Undyne

Sans - Alphys (and vice versa)

Asgore - Asriel

Toriel - Chara (and vice versa)

That's all I can think of, if you have any other swap character ideas then give them

oh yeah and this is what papyrus would probably look like