The craft floated along the hills above the homes, as tho taking a leisurely cruise against the mountainside...While nursing my infant in her darkened bedroom at night, I observed what I first thought was an aircraft flowing low between hills. I became concerned because it seemed to be a large aircraft, flying very fast at way too low an altitude. I watched as it made a turn to fly against the hillside range above my house. Suddenly I realized that not only was the aircraft NOT flying fast, but it was much smaller than I'd thought. I kept watching and realized that the aircraft was sort of "floating" along, not following a direct path, but sort of meandering side to side, and up and down. Sort of like a ball floating on waves. When I could make out details, I found that it had no particular shape, was sort of "opalescent" like a bubble, and seemed to be revolving, but in no particular direction. The strange thing is, when I realized I was not looking at a standard aircraft, I gasped and said out loud "OH MY GOD!" The aircraft reacted, sort of stumbling to a half-stop, and then dashing away full speed. I dropped my child into her crib and raced out the door, 3 seconds tops, and it was already out of sight when I got outside. There were no discernable lights on the craft, yet we had no lights that would reflect on the craft, so the lighting must have been interior. For years I would have a vague memory of that night in the back of my mind, but it was not until my daughters and I saw another strange shape over the San Joaquin Valley and started talking about it, that the memory and all the details of that evening long past came flooding back. Almost as tho a dam had been unleashed. It was the strangest thing.((NUFORC Note: Witness indicates that date of incident is approximate. PD))