Youtube has recently recommended me a video of Feynman allegedly explaining why we couldn't go to Mars and back. I am normally on Youtube for something specific and don't follow recommendations, but hey, it's Feynman and I haven't seen it before, so I had to watch. After a few seconds it has become very clear that the video is totally fake. Then I started digging, and it turned out that both voice and the text it says are fake too. According to the "authors" it was "based on Feynman's work", which is his whole physics course.