Fastwalker captured on video during thunderstorm.

This object moves very quickly from left to right in the lower part of the frame. Its motion is too quick to be a balloon and too straight to be an insect or a bird. Probable unknown. (Note: One of the YouTube trolls comments that his "software" has determined a distance for the object, and that it is an insect. Without knowing its size or having any triangulation points, no such determination is possible, and no software exists that can do it without those inputs.)