While the shape field is important, the description has more information. Let's see what we can do with it.
First, let's examine a few and see what some of them look like. The following example is one that I selected randomly:
Large boomerang shaped invisible object blocked starlight while flying across sky. I have a sketch and noted the year was 1999, but did not write down the day. The sighting took place in the late evening when it was completely dark and the sky was clear and full of stars. Out of the corner of my eye, I noticed movement in the sky from the north moving to the south. When I looked closer, however, it wasn’t an object that I was seeing move, rather it was the disappearance and reappearance of stars behind an object. The object itself was black or invisible with no lights. Given the area of stars that were blocked out, I would say the object was five times larger than a jet. It was completely silent. It was shaped like a boomerang only a little more...