It's a good thing that of the 40,000 or so species of spiders in the world, only 23 are considered social. One of these social species, Anelosimus eximius, gathered for a little party one day in 2013 in Santo Antonio da Platina, Brazil. The next thing the residents knew, spiders were falling from the sky [source: Nuwer]. As they'd say in Portuguese, que horrível!
This arachnid species, which lives in colonies that can number in the thousands, likes to gather together later in the afternoon or in the early evening and create enormous webs to trap insects for their next meal. The webs can be as large as 65 feet tall (19 meters), and stretch from the ground up to tree canopies or buildings. When the spiders are in these webs, they can look like stars in the sky. Normally, they stay in their sticky webs and wait for dinner to come calling. But if Mother Nature calls in some strong winds for the night, the webs can be blown off their anchoring points and carried away. At some point, when the wind weakens, they'll rain down to earth. Hopefully, no one will be in the vicinity when this happens [source: Nuwer].