This is an old style light switch overlay for a standard single-gang light switch.  You don't need to remove the existing light switch cover plate for this to fit over it.

I designed it in Sketchup and printed it on my A1 3d printer.  It is designed to be assembled without any glue or special tools other than a flat head screwdriver which you would need for the coverplate screws.

This design is based on my other Spookin Switch, but is an evolution of the design with updated parts.

Here is a video I made showing how to assemble and install it.