Just past sunset I turned to watch the mountains & saw above the darkened mountains saw a what may have been an extremely large grey cigar shaped object with grey smoke all around it except in the front. The smoke seemed to be traveling with it. It moved exceptionally fast & when it finally went just below the darkened mountain skyline, I could no longer see it. I alerted my husband but he has poor eyesight & was unable to see it as it was traveling too fast for him to catch sight of it. It appeared to be on our side of the mountains & was difficult to tell how far away it was except it looked to be several miles away which makes me feel it must have been gigantic. My feeling was that I was stunned to see this unknown object & actually be able to make out a clear outline of this extremely fast moving object. I was shocked!