I won’t even bother making this a “name this creature” post. It’s not likely that anyone would have seen this exact configuration of living matter, though the small wooly aphids come close in superficial appearance.
This mass of waxy filaments was peeking out from under the back side of a leaf on a volunteer walnut sapling near the back door.
It took some sleuthing to figure it out. The living, moving mass, on closer inspection, appeared to be a caterpillar– the larva of a butterfly or moth. Nope. Not.
It’s official name (and there are two indistinguishable individuals in this image) is the Butternut Woolyworm. Not a worm. Not a close relative of the common wooly worm we’ll see crossing the road about now, that morphs into an Isabella Tiger Moth.
It is the immature stage of a hornfly. Which is not a fly at all but a kind of wasp. And the waxy costume it wears at this stage of life is apparently a way to make itself unpalatable to would-be predators. I certainly was not tempted.