Surprisingly, things cooled down for a few days after Dadster the pun master came along. (another non-intended pun)
This was extremely abnormal, seeing that Sans hasn't made any puns since then. A genuinely concerned Papyrus decided to check it out.
"Sans, are you not feeling well? You haven't cracked a joke in a few days"
"Nah, but I guess you could say…I lost my funny bone"
They stood there for 5 minutes with Papyrus staring holes into Sans and Sans bracing himself for the 4th outburst.
"Sans…you made that joke back in the first chapter"
"Eh, people probably didn't stick around"
Papyrus hoped that that wasn't a pun. He really hoped. But Sans pulled out a stick from behind his back anyway.
His tolerance has of course grown but he had his limits.
Frisk appeared out of nowhere and was holding up a Papyrus-Rage-O-Meter. So far, it was pointing to 'mildly annoyed'.
Papyrus turned around to make spaghetti since it always seemed to calm him down.
"Sans, did you take all the ketchup again"
"Well, you caught me red handed bro"
He lifted his hands to show that they were covered in ketchup.
The meter showed 'annoyed'.
Papyrus was trying hard to control himself.
"Want some skele-buns with that spaghetti bro?" Sans said while holding up a baguette.
The meter went up to 'very annoyed'
"Whats wrong Pap, don't have the guts to fight?"
Papyrus was about to shout but stopped himself.
'Oh god Sans stop' read the meter.
Sans took out a ruler and waved it around.
Papyrus took a deep intake of breath.
"Sans, what are you doing"
"I'm measuring your patience"
"NYEEEEEEEHHHHHHHH"
Frisk ran for their life, dropping the meter that now read 'Run.'