Is it possible to have 2 cameras, 1st with mask to reveal 2nd underneath?

Hello! I was wondering if it’s possible with Unity to have 2 different cameras, both rendering a similar scene, and then mask the first camera with a texture to display the 2nd camera underneath.

Basically, I have a concept for a game where I’d ideally like to have spots on the camera pass by as the player travels through the world, and I’d like the world to be displayed differently in those spots. My idea for this was to have 2 nearly identical scenes with cameras, and then somehow mask the main camera displaying the background camera underneath with a slightly different scene.

With an ideal solution, I’d like to be able to modify the mask on the fly and perhaps animate the mask so I could have moving “holes” in the camera showing the alternate view. Is there a tutorial or example like what I’m describing anywhere to get me started?

Thanks!

Edit: By “scenes” I didn’t mean actual Unity scenes, I meant it in the general sense. I’d like to have 2 different setups of the same game level in one unity scene, and then have the cameras sort of blend together in the way I described above.

You could render the top view to a texture then combine it with a mask texture which would just be a circle (the area shown) and the rest full alpha. Then draw the combined texture as a GUI texture on the top. Probably best to push the drawing to a shader but as a quick test this should work.

Edit:

Also take a look at stencils. Could be a nice way to do it: