At noon this past Sunday, a Swedish power plant brought one of its reactors to a halt over an unlikely issue: a horde of jellyfish had begun clogging up its system. The Oskarshamn nuclear plant is set beside the Baltic Sea, from which it draws in water to cool down its turbines. After the mass of moon jellyfish made their way into some of the cooling pipes, the plant chose to shut down one of its three reactors so that it could clean and unclog the pipes, reports the Associated Press. Had it let the issue go, the plant says that the reactor would have ended up automatically shutting itself down because of its low coolant supply. The reactor is now up and running again and should return to full operation by tomorrow.

But as odd as the story may be, the AP reports that other nuclear plants could soon be having the same issue. A plant in California already encountered a similar problem last year, when a jellyfish-like organism reportedly clogged its own intake pipes. And marine biologists expect that this could happen again. "There seems to be more and more of these extreme cases of blooming jellyfish," Lene Moller, a researcher at the Swedish Institute for the Marine Environment, tells the AP. It's not the first we've heard about the rise of jellyfish either — a recent book even suggests that they could be on their way to dominating the ocean.