Turns out it was the seed pods from the poplar tree, but for a few uncertain moments Emmett and I felt like we had been transported to Pandora.
There was also a really cute video of Emmett conducting the "source of fluff" investigation. Maybe someday I'll figure out how to upload it.
In the meantime, you'll have to make due with this shot of Hunter decorating the veteran's graves at the cemetary across the street.
"Thank you, Sir!"