A few years ago, my dog ate some undetermined quantity of spent corn cobs - the corn eaten off, and cobs tossed, that she got into. Apparently, corn cobs go thru the esophageal sphincter quite easily into the stomach, but are completely blocked by the Pyloric sphincter from entering the small intestine. Oh, and this was somewhat complicated by the fact that the stomach does not really digest a corn cob. There were at least a half-dozen one-hour trips to a vet specialist in removing such things, with a poor drugged pup to bring home afterwards. There were ~ 6 trips for the one meal because the vet found that in our case, it was one snare per cob, and so many cob pieces, that he kept running out. All the while, over a few weeks, she had to eat special canned food that could bypass the cobs, as her nourishment.
We had two GSPs that found an unopened can of sardines in plastic wrap. It had been sitting in a bad on our kitchen table for weeks. One of them ate the whole can of sardines including the plastic wrap and the tin can. Luckily he chewed up the tin can so small that it was just little bits of metal that came out. Still tore him up pretty good, but nothing life threatening.