The: X-files 1x20

In the 20th episode of The X-Files first season, "Darkness Falls," Agents Mulder and Scully travel to Washington's Olympic National Forest to investigate the disappearance of loggers, only to discover a deadly swarm of ancient, bioluminescent insects. The episode is a classic Monster-of-the-Week story where the pair are trapped in a cabin, relying on light to survive the nocturnal insects before being rescued and finding the forest under threat. You can stream the episode on Apple TV or watch it on other major streaming platforms, with additional details found on IMDB and Wikipedia. "The X-Files" Darkness Falls (TV Episode 1994) - IMDb