Scary, Scary Night

It happened a couple of nights ago.  A hissing and bumping outside my bedroom wall of windows.  The sound went on from about 11:30AM until about 2:30AM.  Intermittently.  Of course it woke me up each time.

Finally I got my courage up to get the flashlight and look out the window.  Hoping and keeping my fingers crossed that I did not see two beady eyes, but whatever it is that is making this horrific sound.

I saw nothing.  I looked and looked.  Very disconcerting.  No, I did NOT go out there.

At least the time I had to kill the BIG scorpion in the bathroom, I found it, killed it and that was that.
Not this time.

In the morning I looked for signs of any activity.  Was the fern mashed down?  Were the many flowers eaten?  Were the cushions on the chaise wrinkled.  Nada.

Then I began to hope that whatever it was would not return.  It HAD been here once before, maybe a year ago or so.  But, just for one night.

Not so lucky this time.  Two more times the darn thing has been here.  Each morning I try to figure out where it is when it is here and, of course, what the heck is it?

I've resorted to looking at You Tube videos of animals making sounds when threatened.  My son thinks it is a possum, which at one point there was one in the garden.  I couldn't find a possum video where they were making noises.

Let me describe it.  A growling, throaty, hissing sound.  Nothing like I have ever heard before except for the time "it"was here before.

Yesterday I saw the little black squirrel scurrying through the garden.  The thought crossed my mind, "Could a little squirrel like that make that loud noise?"  Can you tell this has me REALLY perplexed.  I've also thought about the large lizard on the roof.  The coatamundi that fell in the fireplace years ago.  The skunk that goes ambling down the road from time to time out of the canyon.  And, again I say, "What the heck is it?"

Each time I've turned the outside overhead light on, it gets quiet.  You ask why don't I sleep with that light on?  Well, because it lights up my bedroom as though it is daylight.  And, yes the drapes are closed.

That first night it was here, it thrashed around and made so much noise before I went to bed, that I actually went upstairs to see if some people were out on the road cutting the weeds down or something.  It could have been a very large animal with all the noise it made. Like an elephant for goodness sake.

And, that leads to the question, "How the heck does it get in here?"  There are very high walls.  There is chain link on the wall that faces the road to the canyon.  To say that the house is fortified like Fort Knox is  an understatement.

The latest thing I've done in my scientific attempt to determine what it is will make you laugh.  I have folded two beach towels and laid them on the seat of an outdoor chair by the window.  Very comfy.  My thought is it might jump up there and get comfortable, I would open the curtains and see it and finally know what it is.
Each morning I look out to see if the towels have been moved around or anything.  So far, nothing.

Help!  Any ideas?  It obviously, well I think so anyway, is nocturnal.  Your guess is as good as mine..........