One of the Feather-legged spiders, Uloboridae. And likely in the Uloborus genus. The only spider family with no venom. And known for the long first leg with the feathery group of hairs. They make tiny horizontal webs. And this one is shown next to its egg sac. Which looks like another spider. Great if you are afraid of the spider but seems not so great if you are looking to eat one. About fifteen species in the US.