Space Battleship Yamato - Season 2 Episode 11 Desslok, the Vengeful Demon!

Starflies are cute spaceborn organisms that glow like fireflies. To gain favour with Desslok, Gamilon General Garrot devises a plan to loose a swarm of starflies, infected with a metal-corrosive bacteria, on the Star Force. Thinking them cute, Star Force personnel take the starfly bait, even after the bridge crew observes Gamilon ships on the time radar dumping starflies into space. The starflies get loose, and get into the Argo's systems, resulting in system-wide electrical failure. The Gamilon carrier then moves in to attack. Desslok calls to reveal himself to the Star Force, who are surprised to no end to learn that Desslok is still around. But, Sandor and Roister manage to repair the ship's systems in time to fend off the Gamilon carrier. The starfly swarm has managed to infest the carrier as well, making it defenseless and forcing its retreat.