Hello, I've seen a bunch of comments recently that are just grey boxes which take a good two dozen swipes or more to scroll to the bottom of. I assumed they were trolls at first, but I checked one in a web browser today and it's a comment that includes an animated file:

https://lemmy.world/comment/6408456

Screenshot:

Example is from this post: https://lemmy.world/post/10322158

I can find more examples if required.