EDITING: The day was a very long one.  I was tasked to do legal research for a group of neighbors who were opposing an intrusive zoning change initiated by a neighbor.   This group had sent out petitions to the close neighbors who were outraged.  On this evening the Zoning Board was meeting.  My job was to stop the meeting. 

Consequently, my head was deep in local ordinances; I was consumed with searching for a loophole while concerned neighbors were literally knocking at my door seeking updates on my progress.  

Walking to answer the door at about 3:00 pm, I walked past the mirror into the front hall and saw a figure on the mirror. After addressing my neighbors at the door,  I turned and took some pictures while calling to my daughter to come and look.

I could not understand what the substance on the mirror to be