A bible ufo site is the first thing that popped up when googling: history+plague+black+wind+scythe. Here's a quote from the site. (No sleep for me tonight)
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1347 Europe: Black Plague, 1347-50: Reports from this period feature strange cigarlike objects flying low through the sky and dispersing noxious mists. Soon after these objects passed by, plague would break out in that area. Other features from this period similar to modern UFO reports include sightings of mysterious MIB-like scythe-wielding "reapers" clad in black hoods & robes, and mysteriously slaughtered cattle and other animals. One year before an outbreak of plague, a "column of fire" was seen over the Pope's palace at Avignon. A monstrous "whale" was cast ashore at Egemont shortly before another plague outbreak, and numerous times during this period "rumblings like thunder" were heard even when there were no storms. Blazing "comets" were seen numerous times in the heavens - some of which may have been real celestial objects frightening an omen-crazy populace - of which numerous were said to be accompanied by "flames" (aurorae?) hanging low in the sky.
http://www.bibleufo.com/ufos2.htm
I am glad I didn't see this last night....
Luke 21
Things to Come
10 Then He continued by saying to them, "Nation will rise against nation and kingdom against kingdom,
11 and there will be great earthquakes, and in various places plagues and famines; and there will be terrors and great signs from heaven.
12 "But before all these things, (1) they will lay their hands on you and will persecute you, delivering you to the synagogues and prisons, bringing you before kings and governors for My name's sake.