That has to be man made. - That’s sort of like the load of hogwash the hippies made up about the serpent-shaped Indian mounds in N. America; that they weren’t manmade. I’m not a fan of The Twilight Zone. If something looks like a duck & quacks like a duck; I don’t have to wait for it to splat a load of poop on my face to admit it’s a duck! - That reminds me; one day a duck wadded into our living room, plopped a load of poop - splat! - on the carpet - then waddled out like it came in. (A Democrat Duck)
That would be like a Democrat.First they foul their nest,then they sneak in and foul yours.