I rediscovered this conjecture several years ago as a response to sky falls of jelly like substances. I went further and anticipated slime mold produced bubbles of methane to do the lifting. It turns out that i am not alone in these speculations either.
There are three items here all showing up after my own speculations on this blog but showing antecedents as well. I was operating with full cloth and direct evidence to hand needing explanation.
What is needed is high altitude balloon systems with human observers and a long dwell time. We may see something. I reasonably presume that any natural life-form must return to earth to multiply and that brings me back to our friendly slime mold and methane.
Earthquakes, Tsunamis, UFOs, and Sky Beasts
Airborne Anomalies: Rethinking Atmospheric Lifeforms
Atmospheric Monsters Attack!
July 13, 2011