Biology and appearance
Grutchins were designed to tear through starships, disabling them and killing their crews. They had acid-secreting mandibles and a pair of grasping legs that extended from their upper bodies. Grutchins also had armored shells which enabled them to survive in both realspace and hyperspace. Grutchins were mindless and did not need to be trained like the majority of the Yuuzhan Vong's war biots. Upon being launched into combat, they could not be recalled. The Yuuzhan Vong had to destroy them once a battle was completed, because, once released, they destroyed anything in their path.
Grutchins were often bred in large breeding pools on Yuuzhan Vong warships. A lack of queens meant grutchins could not reproduce—a safety measure kept in place should one escape from containment. Grutchin larvae underwent metamorphosis to become mature adults in a very short period of time.
The Yuuzhan Vong were also known to deploy grutchin torpedoes which were massive shells that contained hundreds of grutchins. The sheer size of the torpedo meant that only Koros-Strohna were capable of firing them. Once the weapon hit its target, the shell collapsed after which it released its swarm of grutchins on an enemy ship.
The grutchin symbiote was a miniature version of the grutchin. It was smaller and unable to operate in space. These were used for assassinations and are often carried by Yuuzhan Vong agents. In order to carry a grutchin symbiote, the Yuuzhan Vong host first had to undergo a ritual modification in the form of four grooves cut from the shoulders to the lower back. The symbiote's back legs slipped into these grooves, hooking onto newly formed bone spurs, while the front legs latched around the host's neck. At the host's telepathic command, the grutchin symbiote would launch itself at a target, attacking it with its acid-edged mandibles.
The turfhopper was a giant variant of the standard grutchin. It was deployed against capital ships such as corvettes, cruisers, and Star Destroyers. They could eat through heavily armored hulls within seconds. They were similar to sentinel beetles.
The grutchinya (also spelled grutchyna) was a larger, more heavily armored and more controllable variant of the standard grutchin. They were deployed only in planetary atmospheres and were able to dig through rock. During the Battle of Ebaq 9, grutchinya were deployed along with voxyn to capture or kill Jaina Solo and the rest of Twin Suns Squadron. Also, the Yuuzhan Vong made extensive use of grutchyna during the Battle of Caluula.
- The New Jedi Order: Vector Prime (First appearance)
- Invasion: Rescues 2
- Invasion: Rescues 6
- The New Jedi Order: Agents of Chaos II: Jedi Eclipse (Indirect mention only)
- The New Jedi Order: Edge of Victory II: Rebirth
- The New Jedi Order: Star by Star
- The New Jedi Order: Dark Journey (Mentioned only)
- The New Jedi Order: Enemy Lines I: Rebel Dream
- The New Jedi Order: Enemy Lines II: Rebel Stand (Mentioned only)
- The New Jedi Order: Destiny's Way
- The New Jedi Order: Ylesia
- The New Jedi Order: Force Heretic I: Remnant
- The New Jedi Order: The Final Prophecy
- The New Jedi Order: The Unifying Force
- The New Jedi Order Sourcebook
- The New Essential Guide to Weapons and Technology
- I, Yuuzhan Vong"—Star Wars Gamer 8 "
- The Complete Star Wars Encyclopedia