The person who made it is in the corner, you MAY use it, just make sure you do the following: 1. Download all the costumes 2.(Optional) If you don't want your desktop clogged up, put them into a folder. 3. Go to a GIF-Making website. 4. Upload all the costumes in order. 5. Download the GIF and Enjoy!
-=DISCLAIMER- I do not own the art, or Sans or UnderTale.