I agree it sounds dangerous, but what is this forum or the AMA going to do about it? Unless you can identify the aircraft (get the N number) and report it to the FAA, its just a story. Since you have no idea who it was, what kinda plane it was or how low he was flying, perhaps you should make the story better. It was a Pitts Special N number N5374W flying 5 feet over my house inverted. Then at least everyone on here would believe you saw something crazy.