40 foot long Cigar shaped object with 2 beaming lights transitioning from white to green, very bright, moving in an unidentified motionMe and my brother were driving back from Yellowstone National Park. Driving past Pray, Montana, we encountered a cigar shaped flat disk floating approximately 100 feet away from us. This was about 40 miles outside of Livingston in the direction of Yellowstone. It was very dark out and the craft was hard to see but my brother is very keen. When he saw it approaching, I had him grab the wheel and I had the chance to see it for almost a minute. it had two very tiny yet very bright lights on each sides. They were bright white and transitioned into green and gave the silhouette of the craft away. We were very very close to the object. (less than 100 feet away). The object itself was about 40 feet long. It was able to move very efficiently and swiftly yet it always set itself in a very fixed location. Like it would zip to certain spots back and forth. It was a very upsetting and disturbing experience that left us with a lot of questions. It moved very low to the ground. We believe it may have landed but we were unsure for we were driving past it. I wanted to turn around, but my brother didn't want to, and that was probably a good call because I value my life. We are terrified and we hope no one is in any danger.