What's dark and so massive that not even light can escape its clutches? The answer is one of the most enigmatic phenomena known to physics: the black hole. And this week we explore the workings of these mysterious entities from how they distort time and what what would happen if you fell into one, to why black holes power the brightest lights in the Universe and how scientists are trying to image their interior. Plus, news of a dissolving brain implant, how ultrasound might be making some people sick, and why a real-life spider-man would have to be really, really small...