He is basically UnderTale Sans but in Papyrus body so he has the body of UT Pap but the personality Of Sans. (btw Us stands for underswap)
Underswap Papyrus: hey bro can you get the honey for me..
Underswap Sans: But brother you are Literately 2 feet away from it!
Us Papyrus: but u are too. :|
Us Sans: FINE! But only this once brother. Next time you need to get up and get is your self.
Us papyrus: k, thanks bro.