Board Thread:General Discussion/@comment-32777118-20170805095751/@comment-27345308-20170805160329

Only Toby Fox knows at this point, really. I'm guessing it's there just as a joke. If I knew it had a meaning I would guess it's because Frisk attempted to kill something invulnerable and the game makes fun of him because of that. It also could be telling the player that EXP =/= experience points before Sans tells them that in the Last Corridor.