I am always telling people to look up. That's where the UFOs are. They are far less likely to appear in front of you, though this does occasionally happen too.
Unusual lights like this are more common than sightings of "solid" objects but attract attention because of unusual behaviour like this. Assuming that there are live beings inside, the maneuver they made is impossible with the technology commonly available today. Therefore we have to assume that it was either an unmanned (for want of a better word) drone or probe of some sort, a "manned" alien craft of superior technology or secret technology that the developers on Earth have not yet made known.
What do you think it was Credwheel?