Ah, Sweet Mystery of Life

The construction project next door is at the electrical stage; this guy from the utility company was up on their roof connecting some new wires. It was interesting watching the bucket go up and down--doesn't look like a very smooth ride. But what is even more interesting to me at the moment is the UFO just over the worker's head. What is that thing? It appears again in the second frame after this, although much further to the right, but it is not in the very next frame. My lens is clean. I never saw anything while I was watching the workers. So what/who is it??