I was at home, lying on my bed at 10:50 in the evening. The room was completely dark, and after a few minutes my eye was drawn to an usually bright star-like object outside my bedroom window. It is not usual to see a few dim stars outside my window (the city lights drown out most of them) but this one was unusually vibrant. After watching the star for less than a minute, the object seemed to move westward very quickly, only to stop and hover again. I began to watch it more closely, and it seemed to actively move fluidly back and forth across the sky, two or three times a minute. Each time it would stop and hover once again. It was a cloudless night, and although I regularly see planes and helicopters in my neighbourhood, this made no sound and had no navigation lights.I immediately grabbed my phone (the only camera within reach), and managed to take photos and take a short video. While doing both, I made sure to rest my hands on the window ledge, and brace my arms to reduce any hand movement. In the video the object can be seen repeatedly moving. In the photos, the object seems to routinely change shape, beginning as a glowing orb, then seeming to 'burst', with a clear hole in the middle, and reforming into a circular orb again. It was incredibly unusual. The object made me feel both curious and unnerved, as although it was star-like, it didn't seem natural somehow. The object behaved oddly. Although I didn't feel unsafe, I was unnerved, and eventually wanted to stop watching the object. After about 20 minutes, I stopped observing it, although it was still in the sky, but far further west than when I had started watching.Any insight you could give would be greatly appreciated. Although I'm aware it very likely could be a natural phenomenon, it seemed unnatural and was unnerving enough that I thought I should report it. Thank you!