A copy of the PSX game "Hogs of War".
I say this, because many, many years ago my copy of that game went missing. I searched through my entire house to no avail, and for the next few weeks I would randomly stop whatever I was doing just to search for it again. Eventually, I stopped doing that but approximately every year or so I would turn my entire house inside out yet again just looking for that game. I finally lost all hope of finding it when I moved, and even when the house had been completely emptied it just didn't turn up.
To whoever stole my Hogs of War disc, I would just like to say: FUCK YOU.