When I was a kid we a Boxer who loved to eat the tinsel off the Christmas tree. And when he'd poop, often there were several strands of tinsel left hanging out of his but that someone, often my mom who was not happy about it, would have to pull out. My dad used to laugh and say "he's just being festive".
LOL!
When he was a pup, Chewy used to crawl under the bed and you could hear him down there messin around.
He had real problems getting his poop out back then... Looked like he was eating a whole lot of hair somewhere... Asked the vet about it when she was down looking at some horses for us, and he checked out alright, so she told be to feed him oil for a while to keep him greased up and see how it goes.
Well, it was spring time, and as things go in the spring, my wife wanted me to take the bed apart and move it out of the way for spring cleaning... Which I did, and that's how I solved the riddle.
That dang dog had chewed off every square inch of that black fibrous sheeting that used to be stapled to the bottom of the box spring - and there wasn't a single bit of it anywhere on the floor. He ate the whole thing.
He came by his name honestly :)