Or, you know, if you accidentally typed a YouTube address into the wrong site, and somehow it ended up on your phone. Whoops. It could happen anywhere, even on a layover
Or if you’re uncomfortable with that, Dr horrible’s sing along blog is pubic domain, a bunch of big actors and writers made it during the first writers strike. I think the sequel is too. I think you can still download it off the official website… I’ve got a copy on my phone just in case I find myself desperate for offline content