The whole idea is definitely nightmare fuel, but yeah, it happens. Millions of spiders falling from the sky, as if they were descending from the clouds in a rain shower, until they cover the ground. In fact, there could be spiders floating above you right now! And that's why we invented houses.
Simon Whistler of Today I Found Out explains how spider rain happens, and why it is often seen as a good thing. Not by me! Luckily, spider rain is more likely to happen in Australia, where nature is always out to get us anyway. -via Laughing Squid