The Plasmacaster was a particle dispersal cannon that fired a beam of charged plasma via a carrier rail. The beam would cause massive and deadly wounds to the targeted Kaiju's anatomy. The beam also cauterized the wounds inflicted upon Kaiju during combat, preventing the spread of Kaiju Blue.
Gipsy Danger had two Plasmacasters, one located on each arm. Prior to its update, the Plasmacaster had to be charged by a swing of the pilot's arm and took considerable time to power up. After Mako Mori upgraded and restored Gipsy Danger, the weapon's charge delay was shortened considerably. The Plasmacaster's plasma reservoirs were also fully restored. It was able to fire several shots before being forced to recharge.
While fighting the Category III Kaiju Knifehead in the gulf of Anchorage, Alaska, Gipsy Danger used the Plasmacaster in its first attempt to kill the creature. After three shots to the abdomen, Knifehead was presumed dead by Gipsy Danger's pilots, Raleigh and Yancy Becket.
Moments later, Knifehead recovered and blindsided the Jaeger. Gipsy Danger's left Plasmacaster was lost when the Kaiju tore its left arm from its body. The damaged sustained by the Jaeger was followed by the death of Yancy when its Conn-Pod was compromised. The surviving pilot used the right Plasmacaster and killed Knifehead when he overloaded the weapon.
During the Hong Kong Incident, the Plasmacaster was used against the Category IV Kaiju Leatherback, shortly after the defeat of Striker Eureka, Cherno Alpha and Crimson Typhoon. The entirety of the Plasmacaster's clip was used to kill Leatherback, severing the Kaiju's left arm from its body and eviscerating it. Before departing, Raleigh and Mako Mori "check for a pulse" and fired four volleys into its carcass to confirm its death.
- According to Travis Beacham, the S-11 Pulse Launcher was an early name for the Plasmacaster.
- According to the novelization of Pacific Rim, the extreme pressures at the bottom of the ocean prevented the Plasmacaster from being used.
- In the film, the Plasmacaster is referred to as the Plasma Cannon. During the battle with Otachi, when Mako Mori deploys the GD6 Chain Sword, the name "Plasma Cannon" be seen on Gipsy Danger's HUD.