I accidentally turned on 'use object as camera' by pressing ctrl + numpad 0 and now I can't get it to stop doing that. I deleted all the cameras, and then created a new one, and still it keeps trying to use that object as a camera, and I can't get Blender to switch to a different camera.
I'm adding the file in case there is something glitchy here.

Ctrl + Alt + Numpad 0, or in the Properties Window > Scene Tab choose wich is the active camera for that scene. – Duarte Farrajota Ramos May 03 '17 at 00:42