Plasma Troopers are Space Pirates featured in Metroid Prime. Unlike standard Pirates, Plasma Troopers are equipped with a weaker variant version of the Plasma Beam that was reverse engineered to use against Samus along with the Power Beam, Wave Beam, and Ice Beam. A design flaw renders Plasma Troopers vulnerable to the Plasma Beam. Plasma Troopers are found in the only Phazon Mines, mostly on patrols. They are among the Pirates that the Omega Pirate summons for reinforcements.
- In the NTSC versions of Metroid Prime, Samus can only damage Plasma Troopers with the Plasma Beam and the Flamethrower. In other versions, Samus can kill them instantly with Power Bombs.
- "Science Team is attempting to reverse-engineer Samus Aran's arsenal, based off data acquired from here assaults on our forces. Progress is slow, but steady. Command would dearly enjoy turning Aran's weapons against her. We believe we can implement Beam weapon prototypes in three cycles. Aran's Power Suit technology remains a mystery, especially the curious Morph Ball function. All attempts at duplicating it have ended in disaster; four test subjects were horribly broken when they engaged out Morph Ball prototypes. Science Team wisely decided to move on afterward." —Space Pirate Data (Metroid Prime)
- "Space Pirate armed with Plasma Beam technology. Space Pirates have reverse-engineered several of your weapons, including the Power Beam. A flaw in the design makes these Pirates vulnerable to their own Beam weapon system. These weapons are inferior to your Chozo-designed originals, but still quite potent." — Logbook "Plasma Trooper" (Metroid Prime)