the Thing from 93 million miles

This Thing has started to appear over the past few mornings.  It only stays for about half an hour, gradually changing shape and position. (See extra).  

The sun, streaming through the landing window is bouncing off something at the bottom of the stairs and reflecting it back onto a blue wall.  But just what that 'something ' is mystifies me.  

This particular shape makes me think of a whale, in the depths of the ocean.

with the morning sun
emerging from the darkness 
leviathan awakes