How to stop non-stop scrolling on MacBook Air after connecting a new Magic Mouse?

The only change before the non-stop scrolling on my MacBook Air is a new Magic Mouse.

I cannot stop the scrolling. I cannot go up and force quit. The scrolling is not interrupting even when I turn off the mouse and use the trackpad. If I move the cursor up to the Apple icon the icon does not drop down as it should and the scrolling continues. I close the lid and try to re-start hoping to find a fresh page to go to preferences but when I turn on the page I was on it continuously scrolls.

[Re-Titled by Moderator]