He seems to have a bit of a sneeze and we think he'd managed to get himself stuck somewhere outdoors all that time. No smell of anyone else's house, garage, or shed, just a general "undergrowth" tang. Could have got wedged between two branches or in a thicket (even though he doesn't wear a collar). The torrential rain either lubricated things enough for him to free himself, or gave him the spur he needed to break out. Lots of people have been out calling for him, but he doesn't have the loudest meow. He is somewhat shell-shocked and I have provided a litter tray so he doesn't have to go out until he's ready