Driving home from a BBQ in Portland, OR just after Midnight Saturday June 15, 2013. My son was sitting in the front passenger seat and witnessed with me. He asked me what it was. I slowed the car down as I was taking the exit to I-5 North the other cars slowed down, it was late so not many cars out. I first thought a helicopter but it was much larger and did not have propeller or wings. It had Circular green lights and violet flashing lights. It was very close to us about 100 feet away(?!?) I am drawing a picture of what I saw. I then thought possible military vehicle? It was flying in a figure 8 pattern then hovered over the water. Then I kept driving wishing I would have stopped longer...ugh. What is this? Ethereal experience.