Welcome mat mystery

Just a quick follow-up on my previous post. The welcome mat was in the yard when I got home from picking up Norseman at 10:20 last night. But... it was gone when I left for work this morning at 7:20. It was dark for eight of those nine hours. Flat scrollwork mat not highly visible in the grass. Only four people knew it was there (the three of us and Mr. UnNeighborly).

Curious.