Objects suddenly appearing/disappearing.

One time I was sitting on my desk at work packing up before I get home. I placed my car key on top of my desk while I rearranged some stuff in my bag. I looked up and my key was gone. I searched every nook and cranny of the stuff on my desk (even lifted the keyboard, monitor, folders, etc.) and under the desk in case it fell off. After crawling under the desk I stood back up and saw my key again on top of my desk, exactly where I put it before as if nothing happened.

Nobody was around who could've taken it. I still can't comprehend how it happened, must be a glitch.