When my poodle Zora was a year or two old, she ate something that messed her up, so the vet recommended opening her up. The problem was, if you let it go, it could turn fatal if the object damaged her insides. It went well and she healed up quickly.
Turns out the object on the x-ray was a smooth rock, which actually passed into her colon with the anesthesia and would have passed naturally. I kept it as a souvenir:
