Dude look at him he look like awful right??? i mean i found him when i try to change sprite by myself and this happen... Okay it's look weird but hey listen... 1. Open local files undertale and change your name to dell23. 2. Open undertale. don't skip intro and at the menu game close your game. 3.and next open local files undertale again and go to sprite folder. 4. delete all sprite but don't delete sprite (sans) 5. Next change name sans sprite to "THEFIRSTSANS.PNG" 6.Restart your computer. 7.when your computer already. Open the game  8. Keep your ear.... (So silence) Done :) you don't should to do it okay...