Malvin Badilla, a Costa Rican construction worker, managed to record a very compelling video of a possible disc-shaped unidentified flying object.
The object appears to spin on its own axis and makes maneuvers in a matter of seconds. The witness states that its apparent size was slightly larger than that of a tractor tire, adding that the time was 3:49 in the afternoon.
Author John Shirley, who brought my attention to this, proposed the UFO might be a psy-ops ploy using a UAV. Not a bad guess, especially as such devices are known to exist.