This swap is made with shrinky dink run through the printer.
Shrinky Dinks are plastic sheets that shrink when baked in an oven. There are shrinky dinks that can be run through an ink jet printer. Make sure the packaging says it’s for a printer. There is also regular shrinky dinks for freehand drawing. Both types have clear or opaque plastic. The clear shrinks to a frosted look, not clear. Select your image and print, draw, color or whatever onto the plastic. Cut the plastic to the desired shape. Poke any holes if needed before baking. Read the directions on the packaging for baking instructions. My first attempt, I did toast the edges of my shrinky dinks. The edges were curled and I flattened them out before the plastic cooled.
Shrinky dink paper can be found at your local craft store.