I tried to guess what it could possibly be. A fungus? A collection of bacteria? Something produced by an insect or a frog? Is it even life? At the same time that I discovered all this mystery goop, the whole property was swarming with its annual infestation of non-biting midges (annoying buggers that at first blush might be mistaken for mosquitoes, but they don't actually bite), and I did find lots of midges stuck to the substance. However, I don't know if they accidentally flew into it, or if the substance is in some way related to the insects' life cycle.
Oh, and it gets weirder. I learned that there's even folklore about substances called "star jelly," which seems to be the translucent-slime equivalent of a UFO. People have been reporting sightings of strange gelatinous goop as far back as the 14th century, and some believe that it falls from the sky during a meteor shower.
What do you think? Have you seen this kind of substance before? When I returned to the property a week later, there was no trace of the stuff. Also, most of the short-lived midges were dead, if those insects had any relation to the goop. It remains a mystery. Maybe I'll see it again next year and get a sample.