I'm working on a game with free pixel adventure sprites. The GIF below is a level that the sprite creator put, and I have no idea how to create such a background in Unity (repeat with go down animation).
Background sprite Also added in the end of this post.


The idea is that you should switch the wrap mode of the sprite to repeat, add that sprite to the material of the 3d object background, and add a script to the background that has access to the mesh. Here is a video that addresses the issue. It is 3 min long. https://www.youtube.com/watch?v=c4r4Ul6QrFg. Let me know if you have any questions!