This is Nimda!Sans's Papyrus. Since Nimda is an out!code, when the player reset, he was replaced by another version of himself. However, the copy of Nimda was different, when the human began their first genocide, he decided to simply stop Papyrus from meeting the human. Many resets later, Papyrus insisted on stopping the human, much to Nimda's clone's chagrin. When the human was about to deal the killing blow to Papyrus to FINALLY see what would happen, Nimda's clone took the hit, and the results are seen here. (Lore will eventually receive an update to not be so cheesy.)
Credit to @-PikaRaphii- for Papyrus sprite I edited. PLEASE GIVE ME IDEAS ON WHAT I NEED TO DO NEXT. THIS WAS DONE OUT OF SHEER BOREDOM. Interstellar Retribution remix by brianjcb on YouTube.