I know the feeling.
Once I was borrowing my wife's car for several days. The last day I drove it, I put a Colt Commander under the seat as I pulled it into the garage.
About a week later I go out there to get the Colt, and it's gone. I break out the flashlight and search the entire car top to bottom, with a growing feeling of dread the entire time and sweat beading up on my scalp. Nothing. Usually we keep the car in a closed garage 97% of the time, but it isn't outside the realm of possibility that some punk had snuck in, found the gun, and left everything else in the car.
Just about one year to the day later, I've got the car up on a jack, changing the brakes. I'm leaning in to get the owner's manual out of the glovebox and what do I see but the butt of the Colt poking out from under the seat. I literally rub my eyes like cartoon characters always do. The seats are power adjustable and they have a lot of struts, brackets and shit underneath them. The gun had been stashed in an upper tier of bracketry instead of on the floor where I thought I put it. It's funny I never saw it, probably because the holster was black and I never thought to look UP any of the 5 times I looked under the seat.
The gun was still in its Alessi holster, and being a stainless lightweight model, looked like the day I left it, except for a bit of light surface rust on the hammer spur.