It’s called the Euthanasia Rollercoaster and it is literally designed to kill its passengers. You go up about 20 stories and then come speeding down well over 100 mph, at which point you hit 7 loops that will put over 10 G’s of force on you. The idea was to use it in executions so that people could go out happy. Right now there is only a model, and hopefully they never build the real thing. Sounds like it could be the basis of a very bad SyFy movie though.