LOL... Magic Bear managed to make a hole in the fabric covering our box springs and when he wanted to hide he would climb up inside them. There was no getting him out once he hid!
My previous cat, the bobcat domestic mix longhair, did the same thing.
She hid in the boxsprings because it was cooler in there, and it was 'all hers'.
Truly an odd beast she was.
She was very affectionate, but she dealt with people on her terms.