Invasion of the Army Fleas

OK 2020, you can stop any time now.  Murder hornets, monkeys stealing Covid-19 blood samples, the entire Presidential campaign to date....look, I can take a joke but this is getting mean spirited.

Recently we were up enjoying a visit with the grands.  Their large back yard is a great place for Nature, abounding in frogs, grasshoppers and other amusing life forms.  But recently a series of peculiar "crop marks?" began to appear.  Long, greasy black streaks on the lawn.  

If you are blessed/cursed with an active imagination it looks very much like an invading army on the march.  

And when you zoom in as close as the camera allows the resemblance to orcs does not entirely go away....

At various times of the day these marching - well actually just randomly crawling - columns of critters form and reform into assorted lines of battalion and regimental strength.  How many solitary loners are just creeping about elsewhere is unclear.  Also creepy.

My cursory attempts to ID these on the internet have been inconclusive.  Even this Gallery of Horrors did not give me a clear answer.  Chinch bugs, maybe.  My wife knows a "bug guy" at the county extension service that could likely give us the correct name but "Army Fleas", "Lawn Orcs" and anything else you'd like to suggest should be equal to better monikers.