Someone in our group made the old joke "99 percent of putts that you leave short don't go in." Which led us to discuss what scenario could lead to a putt left short going in.
If someone else's ball knocked your ball into the hole, you have to replace it. If they were on the green, they get two bonus strokes. Either way, you replace your ball, and they play theirs where it came to rest. Conceivably both balls could go in the hole. In that case, you replace yours, and theirs is considered holed (but they still get the penalty strokes, if applicable). Rule #11.1
If the wind blows your ball into the hole, my interpretation is that it matters whether or not you had marked it. If you had marked it, and then the wind blew it into the hole, you would have to replace it. If you had not marked it, then it would be considered holed on the previous stroke. But you only get ten seconds. After that, the ball is considered at rest. Weird. See Rule #13.3.
What if an animal knocked your ball into the hole? An animal would be considered an outside influence, and the ball must be replaced (Rule #9.6)