Scunner is a Category IV Kaiju that was created by the Precursors, and passed through the breach and guards from attack, alongside Raiju and Slattern. He serves as a supporting antagonist in Pacific Rim.
Scunner passes through the breach ordered by its creators, the Precursors, to guard it from any Human attack. Eventually, two Jaegers, Striker Eureka and Gipsy Danger, converge on the breach with the intention of detonating a nuclear bomb to close it off. As the Jaeger's make their advance Scunner charges Gipsy Danger along with Raiju, momentarily taking Gipsy off guard. Eventually, Scunner tackles Gipsy trying to ram its horns through the giant mech, until Gipsy manages to get the upper hand, however just as Gipsy is about finish Scunner off, Raiju intervenes and swiftly tears Gipsy's arm completely off. Scunner then recovers from it's wounds just as Gipsy Danger kills a charging Raiju with it's chain sword, Scunner then takes that moment to attack and cripple Gipsy's right leg.
Despite being critically wounded, Gipsy still gets the upper hand on Scunner by stabbing it through the neck and forcing it's face into a volcanic pit, which severely burns half of the creature's face. Eventually, Slattern, who had come out of the breach and engaged Striker Eureka, calls for Scunner's aid in its exhausting battle with Striker, Scunner knowing Gipsy is crippled, leaves the fight to aid its superior. The crew of Striker Eureka realize that it has already been badly damaged by Slattern, and now with a second Kaiju on the way, they decide to sacrifice themselves so Gipsy can complete the mission, and just as Scunner is about to attack Striker from behind, they detonate the nuclear bomb strapped to their back, which completely obliterates Scunner, and critically wounds Slattern.