Mojang made a website in 2011 where people could add custom captions to a pig sock puppet video and share them, to promote a new line of minecraft-themed socks. However the software on the website that allowed you to do this doesn't seem to be archived anywhere.
the site: https://web.archive.org/web/20110919061749/http://pigtales.minecraft.net/
the video: https://www.youtube.com/watch?v=vLXPyJEFzY0