I was working for a postal contractor and we had to go to the local P&DC (warehouse sized building where all the local mail comes in to be sorted and then shipped to various destinations).

The local foreman was giving us a lecture about safety and things not to do in there, and we were standing there listening to him. To my right about 10' away were a couple of boxes around 2' tall each. I was listening and my eyes were wandering, taking in the gigantic space when suddenly, out of the corner of my eye, I saw the box move! It like tilted a little and there was definite movement inside (it had a slit in it)! I yelped like a little kid: "that box moved!"

The foreman nonchalantly dismissed it saying, "yeah those are ducks being mailed". I was shocked to say the least.