Low flying/hovering egg shaped object seen in southern california w/video.

Good evening around 1845 on Thursday Oct 24 2019 my wife and I were driving Northbound toward Los Angeles on the 405. As we were passing through the town of Anaheim we noticed a unusual egg/oval shaped object that appeared to be floating then suddenly moving downward and upward erratically. I quickly pulled out my phone to try and capture what we were both witnessing.
What we were seeing was approximately 100 yards off the highway and seemed to be above a parking garage by the looks of it. The color of the craft was grey in color with some shimmery texture to it. It appeared to be maybe 10-15 feet in height but was hard to tell as we were driving and it was moving frantically. I looked online on multiple sights and asked on multiple social media sites to see if anyone else that was around witnessed the same thing.
I was able to get a decent 20-25 second video of the craft which I will attach. The first thing I thought of when I saw this was that it’s a big balloon that usually car dealers put on the cars if they are having a big sale of some sort. But after getting closer and than witnessing the object quickly come down then go back up I realized it couldn’t be a balloon cause they do not move that erratic or suddenly. Also there was no strings or anything attached to this thing. What I could tell this object was approximately 75-100 feet in the air.
A little background on myself, I have noticed unusual objects flying since moving out here in California 4 years ago.  I’m 28 years old and am a Marine Corps OEF combat veteran.  Served just over 5 years before coming out here.  After that I worked for the government as a contractor and was around aviation heavily so I have a strong deep understanding and knowledge of aviation and in general flying.  This sighting was for sure a bit off and it wasn't anything iv seen nor know of that would be able to maneuver the way this thing did.
Hope this was detailed enough and I was able to shed some light on the issue.  Stay vigilant.