actually I think what happened is that some jerkbutt on tumblr changed the link in the original post to something that was harmful (malware or virus or whatever it was) so that when people reblogged it from them they got the warning that it was dangerous. The app is a real thing (like I said I got it and I've had it for a full 24 hours or more on my computer and I used it and absolutely nothing weird has happened). Although right now the site where you can download the app is down because of too many people visiting. But really the original thing is harmless, and actually pretty quality (I made a gif out of it here to test it out, it's not bad for a free program). So once again, it's chalked up to lots of misinformation and confusion à la tumblr