Stepped outside before heading to bed. I was looking up to see if the big dipper was in view that late. The sky was clear and cloudless. Out of the northern horizon I caught movement. I caught direct visual and watched a boomerang shaped craft fly from a N-NW to south path.

What I found to be unsettling: dark smoke color, no navigational lights, no sound at all - mid-low altitude, no more than 10,000 feet in altitude.  Speed was alarming as it took 5-7 seconds to cover the direct route.  
The shape was nothing I have seen.  It was not a flying wing.  Chevron is close, boomerang is in my opinion the best way to describe.  Thin but congruent, rounded wingtips, no fuselage.