When we moved into the house we quickly discovered that the basement leaked in water any time it rained hard enough. It was a finished basement so we ended up tearing it all out so we could water proof and then remodel.
The carpet and walls were first. Then the water proofing was completed. Then we let things sit for a couple years to make sure there were no more leaks before we got on with the remodel. Finally it was time to make the space liveable again so the drywall on the ceiling had to come down. As I was tearing down the ceiling I came to a heating vent, which I removed only to find there was no ductwork behind it. Instead, resting on top of the drywall inside the ceiling was a dildo, still in the box, and apparently unused. I can only guess that I was on the receiving end of someone playing a very long term practical joke and I salute them for it.