Anyone ever received a bonus rock with their watch parcel?…

So I was waiting on a delivery from my German post forwarding box of a Tissot that I’d bought out of Italy. Had issues with UPS holding it and wanting more fees and it seemed to take a while through Customs too.
It arrived today and felt heavier than expected. Opened it up to find a wrapped rock…

First thoughts were I had been scammed. 🤨 our receptionist was next to me as she loves seeing all the unboxing of the random vintage crap I buy and she is also a watch girl. She was baffled too. Was about to start furiously messaging the seller but then in the bottom corner of the box I found my watch tucked away! 😅 Has anyone ever encountered this before?