The grutchin was a Yuuzhan Vong bio-weapon, engineered for combat, that bore a resemblance to a winged, black insect of the locust type, measuring about half-meter in length.
These creatures were biologically designed to penetrate starships, rendering them inoperable and eliminating their crew. They possessed mandibles capable of secreting acid, complemented by a pair of grasping legs extending from their upper bodies. Their armored shells provided resilience in both realspace and hyperspace environments. Unlike most war biots of the Yuuzhan Vong, grutchins operated without intelligence and required no training. Once deployed into battle, they could not be retrieved. Because of their indiscriminate destruction, the Yuuzhan Vong were compelled to eliminate them after each engagement.
Typically, grutchins were cultivated in large breeding pools aboard Yuuzhan Vong warships. To prevent uncontrolled propagation, they lacked queens, ensuring they could not reproduce if they escaped confinement. Grutchin larvae underwent rapid metamorphosis into fully developed adults.
The Yuuzhan Vong also utilized grutchin torpedoes: massive shells containing hundreds of grutchins. Due to their immense size, only Koros-Strohna were capable of launching these torpedoes. Upon impact, the shell would rupture, releasing the swarm of grutchins to attack the enemy vessel.
Their initial encounter occurred when they assaulted Kyp Durron while he was piloting his X-wing. Although he managed to overcome them, their origin remained a mystery to him.
A smaller version of the grutchin, the grutchin symbiote, was incapable of operating in space. These were employed for assassinations and were frequently carried by Yuuzhan Vong agents. To accommodate a grutchin symbiote, the Yuuzhan Vong host had to undergo a ritualistic modification involving the creation of four grooves extending from the shoulders to the lower back. The symbiote's back legs would then slot into these grooves, attaching to newly formed bone spurs, while the front legs secured themselves around the host's neck. Upon the host's telepathic command, the grutchin symbiote would launch itself at a target, attacking with its acid-laced mandibles.
The turfhopper represented a gigantic variation of the standard grutchin. It was deployed against large vessels such as corvettes, cruisers, and Star Destroyers. These creatures were capable of devouring heavily armored hulls in mere seconds, exhibiting similarities to sentinel beetles.
The grutchinya (sometimes spelled grutchyna) was a larger, more heavily armored, and more easily controlled version of the standard grutchin. Their deployment was restricted to planetary atmospheres, where they could burrow through rock. During the Battle of Ebaq 9, grutchinya were deployed alongside voxyn units with the objective of capturing or eliminating Jaina Solo and the other members of Twin Suns Squadron. The Yuuzhan Vong also utilized grutchyna extensively during the Battle of Caluula.