Double-click flag so that the music syncs! Press F to attack Sans! (Wouldn't recommend doing it. You might have a bad time.) You can replace characters by going into their costumes and replacing the poses with your characters' poses. You can also change some of the animation code if you want it to look different. Alright nevermind I lied it's fixed now.
Credit to @BlueTheEpicKid for the assets. You can find them here! https://scratch.mit.edu/projects/670284524/ https://scratch.mit.edu/projects/674662284/ I edited them a bit. Credit to Tenzubushi for Sansational. Credit to the Indie Cross team. Credit to Toby Fox for the sound effects and creating Sans.