It folds closed and my cat won’t crawl in it. I even tried rubbing catnip around inside it. 

It does work along with a tied off pillow case as a cat protective cover for vet visits! My cat freaks when I put her in a carrier, so I put her in a pillow case and close the end with a rubber band. She got very ill and I had to take her to the vet in sub-zero temperatures, so I gently slid the pillow case down into the tunnel and carried her like that to keep her warm! Worked like a charm!