On the evening of June 6,2015, around 10:15, I was letting my dog out into the yard and looked toward the sky as I waited for her. I was looking directly eastward at a treeline about a quarter of a mile away, maybe half a mile, and from my perception, about 20-40 feet above the treeline and very slightly to the right of it, I saw an extremely large shape in the sky, very sharply pointed in the middle extremely long in its width, which all of a sudden just seemed to slowly appear. It almost reminded me of an arrowhead or zig-zag chevron in its width, but the sharply pointed center looked like the two sides of a triangle. In the middle of it, above the largely pointed center, was a round shape that almost looked like a dome. I could not see the length of it as I was looking directly at it as it was heading west, and just could see the front and width of it, which was extremely large. It was moving very slowly, not fast at all.It is difficult to judge by measurement the size of what I saw without using the words huge or large. If I stand in the same spot where I was standing when I initially saw it above the treeline about a quarter to half mile away and hold up a quarter at arm's length, then I would have to hold 3-4 quarters across to cover the width of it at that distance. As I continued to stare at it, I just froze and tried not to blink. I was stunned by what I was seeing. I then saw what looked like a hot sidewalk effect, for lack of a better description, or a waviness that began to encircle it, and then it looked as though piece by piece I could see through it until it would fade or melt into the sky - almost as though it was camouflaging itself in the night sky - only to reappear slowly again several seconds later. If I hadn't been looking in its direction at the moment I did, I would have missed it, despite it being so large, because of the way it sort of fit in with the night sky when it would show itself. As it came a little closer, I noticed lights from underneath it, but then I also noticed that it faded in, or disappeared, more frequently and that its shape became sort of lost or not as discernible as it had been. What did become more discernible, however, were the lights underneath it. By the time it was nearing my home, I saw one large circle with about 15-20 red globes of light within the circle. I then realized the lights were underneath something, but the object was not discernible around or over the lights at this point. Everything looked just really dark, but I knew it was there and I sensed it was there. I'm not great at measuring distance, but the circle of lights was perhaps about 10-15 feet around, maybe a bit more, about 400-500 feet up. It was totally silent. I saw the circle of lights then move very slightly and slowly in a northwesternly direction above my home. The lights did not move, but the entire circle moved with the lights inside it. At this point, I became afraid and grabbed my dog. I ran from my back door through my house to my front living room window as it faces north, to see if I could follow it, but when I looked out my front window it had disappeared. It was just gone.I live fairly close to a Chicago airport (about 30 minutes south) and am very familiar with the sights and sounds of airplanes, whether they are flying high or low, daytime or nighttime, but this was not like anything I had ever seen before in the sky. It didn't make one sound, and was very large. There are always planes flying in their flight paths over my neighborhood and my home, but strangely enough, there wasn't one plane in sight during that time that I could see or that I could hear. Just silence. My husband and son were not home at the time, and I did not have my cell phone on me when this occurred as I was just letting my dog out and had left it in the house - never imaging that I would be witnessing something like this - so unfortunately, I can only tell you what I saw with my own eyes.After telling my husband and son about my experience, my son showed me pictures of a stealth bomber, which was not what I saw in the sky. They also showed me pictures of Chinese lanterns, but the lights that I saw did not resemble Chinese lanterns whatsoever. I also was shown pictures of an Aurora fighter plane - again, no resemblance at all to what I witnessed. If anything, when the object would sort of fade away, and as crazy as it sounds, it almost reminded me of the movie, Predator, with that same kind of waviness and morphlike appearance.This was such an unnerving experience for me. In some ways, I wish I had never witnessed it because I can't get the image of it out of my mind. I only wish there was some explanation for it, or that someone else has also seen something similar, which is why I'm posting my story. I had actually called the NUFRON hotline and the person I spoke to told me to contact the city newspaper. I was very hesitant to do that as I want to remain anonymous - I would most certainly be labeled crazy. I know how incredible this may sound, but it is the total truth. I'm still shaken up after witnessing this. I look at the sky differently now. I know what I saw, no doubt about it. And I can tell you, without hesitation, that this was most definitely not an airplane. The enormous size of it was no match for an airplane. I have no idea what it was that I witnessed in the sky that night.