That was the fish hook that our foster pup swallowed last night at the river. She was saying hello to some young people who were fishing near us and one of them put his line with bait still attached down near her. At least he was nice enough to bring her over and tell me. Pup barely seemed to notice. She was still trying to eat dead bugs!
Trip to the emergency vet (took us an hour to get there), but fortunately it only took them a couple of minutes to get it out under anaesthesia (the pup's 4 months old - no way to do it without knocking her out cold). That cost us most of what her adoption fee will be though.
Then when I got the pup home, still pretty sleepy, she seemed to be having a massive cramp in her hind leg. She was crying loudly and biting the leg that seemed to have a life of it's own. She screamed when I touched it too, but I finally got it to stop by encouraging her to trot to the backyard and back.
She's fine now. Though still smells of fish bait.