I know that there is a counter for the amount of kills on the stats menu. I know how to open "file0" to hack my location and items. All I need to know is where in "file0" is the kill counter to change a property to (insert amount of kills needed to have Sans ask if I want a bad time here), the codes for the items needed (I already hacked the real knife into the game), and the room code for Sans' bossfight.

(I'm not very good at making "complete" questions yet so edit if you think something I said was unclear)

2 Answers 2


If you just want to practice, beat, or just experience the fight without playing the game, there are solutions other than editing your save file. You can find a recreation of the fight here and play it at your leisure. There are also several videos depicting the fight on YouTube.

The actual process of getting a save file is very complicated because of the various checks to make sure the game data is logically consistent, so it's honestly not worth it. Playing the game and grinding through fights is so simple during a genocide run that it would take less time to get to the fight properly than to learn how to edit the files without corrupting anything.

  • 1
    Even though I killed Undyne with the Real Knife - a weapon I can only get at the end of the game through genocide, but still got it on my neutral route, and never corrupted my game. (It might be because my game is cracked in a way) I have played through the boss fight on Scratch multiple times and just want to try out the real game, not the simulation. (That recreation you provided got blocked by my school's firewall on Chrome) Commented Dec 16, 2020 at 12:04
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    And in my "cracked" version, I found a folder just for Undertale saves, so I found my answer. Commented Dec 18, 2020 at 12:47

All I had to do was dig deeper into the files on my "cracked" version and found a set of saves...

  • After Genocide Final Boss
  • After Pacifist
  • Before Genocide Final Boss

I copied my saved game to this folder and replaced the files with the "Before final boss genocide" and I got to Sans. With a burnt pan. And all healing items.

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