According to a video uploaded to YouTube on Feb. 7, spiders appear have taken to dangling from the city's electric lines and other surfaces in Santo Antônio da Platina, Brazil.
These seem to be fairly large critters, too, plainly visible when the camera is zoomed all the way out, with a rough approximation of size given by nearby transformers on the electric poles.
It isn't immediately clear why these spiders are congregating in such a manner, but it's worth noting several species of arachnid cooperate in colonies and weave (ahem) fairly extensive social networks.
Leticia Avilés, an arachnid expert at the University of British Columbia in Canada, previously told New Scientist that of the estimated 39,000 known species of spider, only 20 or so have been documented to cooperate.
Anelosimus Eximius, one such species of "communal" spider, inhabits tropical environments throughout South America. Scientists have determined that social spiders work in teams to catch much larger prey than otherwise possible.