New Garden Inhabitant?

I didn't know if I should post this and considered waiting. But I need feedback, so...I'm posting it here and would like to know what others think and what I should do (if anything). And no, I'm not some old looney-tune. (At least not in MHO.)

A little background...my wife and I went for a trip to Pennsylvania to witness middle son's college graduation and do some sight-seeing. We were gone for ten days. My other two sons were at home, but say they didn't go into the backyard, and they claim they don't know ANYTHING.

I looked at my garden and noticed a bit of color that I hadn't expected to see. I got closer to investigate and took these pictures.

That brown object next to the tree trunk is a "tiny" house, barely larger than a bird house and is complete with door (that doesn't seem to open--no handle and appears to be stuck and window opening with shutters.

This is a side view showing the window opening.

This colorful fence is what first caught my eye from our back deck.

I shined a flashlight in the window, but couldn't see a thing. The door doesn't open, so I don't know if this "house" in my yard is inhabited.

Stranger things have happened to me, but nothing comes to mind immediately.

WELL...a new wrinkle has emerged since my last post on this subject.

Here is the latest development.