Don't do this. You'll waste hours!
I have yet to meet anyone who works with video that hasn't tried this at some point in their careers. You point a camera at a monitor displaying its output. What happens next is a moving kaleidoscopic display of light and colour that looks like it has been generated by a sophisticated fractal computer algorithm.
At times the effect is completely magical. And sometimes it's just plain disorienting.
This was one of the first real-time video effects. Remember the opening title sequence from Dr Who?
Of course that was in black and white, and using the special British low-definition system, 405 lines.
When you see what you can do in HD, it's pretty mind blowing. I'd love to see someone try to recreate the original Dr Who opening sequence with modern, 4K gear.
Here's basically a video of someone playing around with an HD camera and a monitor. At points, it definitely gets trippy.