We received a box of knitting supplies once that had two pairs of pliers in it. No invoice entry, no note, just two pairs of pliers. The box had been retaped (UPS uses cheapass clear tape so you can tell, I'm not sure what the post office does) so we just assumed it had broken open in the warehouse and the pliers got tossed in in the course of putting it all back together.

Weird shit happens in those warehouses, I tell you.