On Saturday November 7 at exactly 6:00pm Pacific Time while sweeping the driveway with a broom at my home at Trinity Drive, Menlo Park, CA my wife came out of the house with my 3 year old son, and said, "okay, we're ready to go to dinner" and then she immediately said, "Honey! What is that thing in the sky!?". I looked up and was instantly amazed at what I was looking at. The 3 of us watched it in awe for several seconds before I pulled out my iphone 6S from my pocket and captured the following video: https://www.youtube.com/watch?v=LL23lVBM-Vo At the first moment I looked up and saw the object, a very bright white/blue beam of light emanated from the rear of the object and it shined through the center of a cone shaped cloud of light (maybe 60-70 degrees in angle from the source craft towards the rear). The cone shaped cloud of light was much brighter to the naked eye than it appears in my iphone video. It was white with a slight blue tint to it and a clear demarcation point at the edges of the cone. The main beam was more blue in color than the cloud around it and the light beam close to the craft, at the source, was bright white. Very bright white - much brighter than commercial airliner landing lights. There is always lots of air traffic over my house for both SFO, SJC international airports and a host of smaller/light aircraft from the nearby local municipal airports. As I have seen UFOs before, I am always careful to observe the sky and can easily discern conventional aircraft from non-conventional aircraft. This was a non-conventional aircraft. I did notice smaller aircraft in the vicinity both before, during, and after the incident. Surely, a couple pilots noticed this phenomena.From the first instant I observed the object to the moment the bright light extinguished, the intensity of the light was slowly dimming. It was the most brilliant when I first noticed it and then became slowly "dimmer" as the object traveled in a North Western direction until the light finally softly died out. Once the bright light source died out, the trailing white-blue beam and the large "plasma-like" cone-shaped cloud remained glowing and very visible for a few minutes. The craft itself was also still visible as a dimly glowing object. Again, no blinking lights or conventional aircraft lights. The shape of the craft was difficult to discern but my best guess was a triangular shape. No visible wings/tail structure could be observed and there was absolutely no sound. The craft seemed transparent or translucent with only a faint glow around it. I assume it was cloaked. My wife and I tracked the craft across the sky for several minutes until we could no longer see it. The craft's course did not seem to change.This was the 3rd UFO sighting I have witnessed in the past 10 months and the first time I have reported a sighting. This sighting was the most profound I have witnessed of the 3 I have seen and it has strongly impacted me psychologically.