Recorded three small, grey, metallic, spherically shaped objects flying together half a mile away from my apartment

I looked out of the window of my apartment upon which I saw three grey, metallic, spherically shaped objects flying outside. The objects were approximately half a mile away, flying at a few hundred feet above the ground. They appeared to have be relatively small (perhaps 10 feet in diameter), flew in conjunction with one other, and did not appear to be flying sole with the wind. They moved at relatively low speeds and did not appear to possess any visible forms of propulsion. I have a video of the encounter on my phone, spanning a minute and six seconds long. I currently a student at the University of Florida. I was the only person in my apartment to witness this incident.
Appears to be 3 balloons tethered together.