On the evening of the sighting, I was in the upstairs bathroom of the sighting location residence, preparing to shave my face for the following day's employment site work. Glanced at the wall clock in the room, as I opened the bathroom's exterior window for cooler air circulation into the room, and noted that it was showing 9:12 pm, MDT. Upon opening the window, I noticed a bright, steady, unchanging, radiant source of white light in close proximity to the tops of the initial foothills located in the area westward of the sighting location residence, between due west, and west,northwest. Initially determined the light source as most likely being a light pole in use upon the nearest hilltop, that I had just not previously noticed in use, before. As I was in process of turning away from the window, to resume my face-shaving activity, I detected the object begin a slow, linear, movement trajectory towards the general south, which then caused me to re-evaluate the object as most likely being the headlight glare of a slow-moving automobile upon some hilltop road/trail that I had never noticed before, upon the particular hilltop area of the object's location. As I was in the process of again determining to turn away from the window, I was suddenly, moderately surprised & shocked to observe the traveling object seemingly to stop its movement, and execute a rapid drop in apparent altitude of seemingly a few hundred feet, before apparently being able to arrest the plunge in the altitude and coming to a stop briefly. Towards the lowest extent of the decrease in its altitude, the object's light radiance changed from the steady, unchanging nature, to a seemingly random flickering of varying intensities, which was maintained throughout most of the remaining sighting duration. Initially thought that whoever it was that had been driving along the supposed hilltop road/trail, had somehow gone off of their travel path & slid about 3/4 of the way down the hill's slope in accident. After the brief arrestment of the altitude plunge, the object then began to haltingly ascend back in altitude, until it was again back at its seemingly original altitude, where it again stopped movement briefly. Realizing the re-establishing of the original altitude was beyond the capabilities of any automobile within the time that it took the object to execute such, I realized that the true nature of the object was something unconventional, and worth continued observation. After the brief stop, upon the regaining of its former altitude, the object then began the same, slow, traveling speed, although now on a generally northern trajectory. While the object was performing the flickering aspect of its light radiance, reduced glare intensity from the object was occasionally low enough to pick out more detained features of the object generating the light radiance. Object appeared to be a structured construct, of a roughly raised-dome shape, with the white light radiating from the domed area, and from what appeared to be a series of rectangular panels spaced around the circumference of the object's lower 1/3 area. After slowly traveling back to the general north for a short distance, near where the object was originally noticed, the object was observed to repeat a virtually identical rapid drop in its altitude & seemingly struggle to get such halted and original altitude level re-established, and stopping briefly, yet again. Object appeared to be suffering performance difficulties involving its altitude maintenance, and after the brief stop in movement upon regaining its former altitude the 2nd time, the object was observed to again resume a generally southward trajectory, until it appeared to land upon the top of the nearest hill along the newest trajectory. The object then appeared to just sit there on the hilltop, with its light radiance still in the random flickering nature, for about 1-2 minutes before I decided to relocate myself to the residence's rear yard deck area, to see if I could improve observational abilities by being outdoors, with the wall clock glanced at showing then 9:16 pm. Upon exiting the residence and stepping onto the rear yard deck, noticed that the object was still sitting upon the hilltop, and a glance at a watch indicated 9:18 pm. Total time spent observing upon the rear yard deck was 10 minutes, until 9:28 pm, before I went back inside of the residence, and back to the upper floor restroom, again. While observing upon the rear yard deck, I detected the approach of a conventional, small passenger aircraft in my side vision field to my right (north), by its engine sounds and safety lighting, and recalling having read about such objects displaying reactions to approaching aircraft, I began to observe the object intently, with just the barest of glances at the approaching aircraft, to keep track of its general position in relation to the landed object. The conventional aircraft was on a generally north-to-south trajectory, traveling in between my location and the object, with what appeared as closer proximity to the objects area, than my own, and was traveling at an altitude of approximately 2,500-3,000 feet. When the conventional aircraft approached into the area to the northeast of the object, I observed the intensity of the flickering glow from the object seemingly stop the flickering activity, and assumed a steady glow again, as it seemingly reduced the power output into the glow function, drastically reducing the glow intensity down to just barely existent at all, to the level that if I had not had the object under direct observation at the moment, then I would have had high difficulty even noticing such a weak light source if casually eye-scanning across the general area of the landed object. The object was observed to maintain the extremely weak light glow throughout the area of passage of the conventional aircraft, until the aircraft had progressed to a point to the southeast of the object's location, whereupon the object then seeming powered back up to its former flickering light radiance & intensities. Observed the object landed on the hilltop for a few more minutes, before deciding to head back into the residence, and resuming my face-shaving activity. Upon re-entering the bathroom area again, I glanced at the wall clock, which indicated 9:29 pm, and I brought the object under observation again, through the room's exterior window. After about 1 minute of observation, the object appeared to slowly take off & start ascending into the air once more, then suddenly began a seemingly unstable, erratic set of movements, giving the appearance of the object not only still having altitude maintenance control difficulties, but now directional & attitude control issues. Object seemed to take several seconds to get the erratic movements stabilized enough to bring the object to a stop once more, before then very slowly moving off deeper into the foothills area on a northwestward trajectory, while seemingly increasing its altitude slightly, until it was able to apparently land on another hilltop. Object remained on the 2nd hilltop for another couple of minutes under my observation, before I glanced at the room's wall clock at 9:36 pm, and resumed preparation for my face-shaving activity. At 9:37 pm, glanced at clock again, before observing the object still sitting atop of the distant hill for 2 minutes (9:39 pm). Kept preparing to shave, with glances back out the window to confirm continued presence of the object upon the hilltop, at 9:40 & 9:41 pm, before beginning actual shaving activity. Upon completion of shaving, glanced at clock again, showing 9:54 pm, and upon glancing out of the window to observe if the object was still present at that time, which I could no longer detect any sign of the object in the general area. Finish bathroom activities, and went to bed, for the evening.