A YouTube video by 20-year-old Erick Reis shows hundreds of large spiders dangling from electrical poles and other elevated surfaces. The spiders have formed a gigantic “sheet web” that extends across the sky.

Brazilian news source G1 reports that the spiders are Anelosimus eximus, which is a “social” spider known for its massive colonies found in South America. Social spiders work together to catch predators that would be otherwise impossible to trap.

Of the 39,000 different species of spiders known to man, only 20 of them are believed to cooperate to build extensive social networks.

The biologist also characterized the phenomenon as “normal”, but with webs that large, one can’t help but wonder what (or whom) the spiders plan on catching.