The funniest story I ever heard about losing a knife was on this very website a loooooong time ago....
The details are a little hazy, but IIRC, the guy lost his knife down the shitter! He unbolted the toilet expecting the knife to be gone down the hole forever, or maybe right there in the chute, stuck. Can't remember. It had been a while since he lost the knife. I think he said he had bought a new toilet, so he took a sledgehammer to the offending porcelain god with righteous and furious anger. There, in the middle of the debris, covered in the worst stuff you can imagine, was his lost knife. I remember it being a Microtech of some type. Maybe a Socom. His description of said event was hilarious!
I would've just said "well, that one's gone forever...."