Amazon has them if you don’t mind paying six times as much as you would at a dollar store.
Cute Yellow Round Sucking & Vomiting Lazy Egg Yolk Vent Stress Tricky Game Relief Toys by Juicart https://www.amazon.com/dp/B01LETPP3W/ref=cm_sw_r_cp_api_i_WRBKNXBGQNTX9Y66MEGV
There are probably other options, but the app I use for it is GIF Live Wallpaper. It's a little fiddly, but it does the job.
For GIFs like this which aren't already in the right ratio for a screen, you can either stretch the gif to fit (which will look rubbish), or choose a background colour - thankfully with this one being on a plain black background you can just pick black and voila.
Hope that helps, let me know if I can advise on setting it up :-)