I just found out that I can make mpv draw to the root window, so I want to try out some animated wallpapers.
Post some nice GIFs and webms.

This is the command, for those who are interested:
$ xwinwrap -ov -fs -- mpv -vo x11 -wid WID path/to/video

You need xwinwrap for this to work with a composite manager.
(If you use a DE you probably have a composite manager, if not install compton)
Check this thread for more info: https://github.com/chjj/compton/issues/226

I don't know how to make this work on windows though.