do you know what the file name is for this gif by any chance?
It's in this background gif, and it's included in the game assets files. It is 72MB big so if you check the assets files it should be easy to find.
Edit: I did the research for you.. for this background it's this file: https://img.itch.zone/aW1nLzEyODE0NDUuZ2lm/original/TYouqL.gif
For the game assets, I don't know as I deleted the file, but if you open your game directory and order by file size you'll spot it easily :-)