I like the "Million Dollars but..." series. It presents interesting thought experiments that I enjoy. Gavin and Geoff really started this off on some of the Let's Play shows they did together. Gavin brought this concept over to the RT Podcast and one of the scenarios was "Would you take one million dollars if there were a snail that followed you and if it ever touched you you would die?"
It's presented in a funny way; the snail is cute and cartoon death is usually humorous. But it wouldn't be funny with real people, of course.
The perfect example of this is a movie called It Follows. It's brutal. Basically, there's this entity that follows you until it kills you. This entity will slowly walk to you until it gets to you and kills you but there is a way to put the entity off you: have sex with someone. In other words the entity is the world's worst STD.
When you have sex with someone the entity then goes after that person and, yet, that doesn't completely get you off the hook. If that person gets killed by the entity then the entity goes right back to hunting you. The story wasn't clear, but I think you only get added to the entity's hit list if you have sex with the current person it's hunting (otherwise there would be a branching nightmare of death).
It Follows is a well done movie and I think you'd like it if you're in to horror movies. The movie follows the story of a pretty high school girl who gets hunted by the entity and how she, her sister, and her friends deal with the entity. This movie definitely isn't for kids but if you like horror movies then you should give it a try. Here's the trailer.