How to stop Docker?

Question

ubuntu

I sat down to pick up what Docker is.
Launched docker run -p 8088:8080 hello-world
Simple Hello World on Node.
And now it won't turn off. How to turn it off? ctrl+c, ctrl+d doesn't work. docker stop hello-worldalso does not turn off the application. Console is dead. What is this nonsense?
Ubuntu 16.-04