Wooly Aphids

Out for Halloween, are these Wooly Aphids - Prociphilus tessellatus. Also gray insects above the white moving insects. They’re called wooly aphids, and they live off of tree sap. And the white fuzz isn’t actually fuzz, but a waxy substance that the aphids produce as a sort of protection.

These are not native, but have immigrated from Japan. They can cause some trouble for your yard from what I understand, because the larvae often congregate on tree branches and do some harm to the trees in such large groups.