I don't think you need to have arachnophobia for this to be a nightmarish scene. I just watch a twelve second clip and my skin is crawling.

The Parawixia Bistriata spiders of Brazil have been raining down on the countryside and it's worse than it sounds. The eight-legged creepy crawlies actually weave a gigantic intertwined web that takes up a whole lot of air space.

The cloud-sized webs are used to catch prey and are so fine that the human eye can't see them. So it just looks like spiders are raining down.