Nemacyst are flying organic bombs released by Seeders. Although they seem delicate and harmless upon their initial launch, they soon fix their sights on a target and accelerate. They detonate upon contacting their target and inflict heavy, usually lethal, damage. They seem to have weak red glowing eyes for targeting enemies. It has been confirmed by Epic that Seeders are fed Nemacyst in The Hollow, and then pass through the Seeder and enter the battle. How the Seeder knows when to release them is difficult to say, as their heads are underground.
The small appendages on the Nemacyst's abdomen appear to be reminiscent of the small legs on the Stomach of a Corpser, and those of a Seeder, giving further weight to the theory that the Locust are not an association of different species, but rather different variations of the same genetic structure. Nemacysts could also be larval Reavers as they both fly by unknown means, have tentacles, and explode in an inky mess upon death.
It is interesting to note that it is not known how Nemacyst find their targets. They could possibly use a bat-like sense of hearing, due to the unspecified nature of the red lights on their outer shell. This however would be difficult, seeing as they are launched in the heat of battle and do not commit fratricide, despite COG and Locust soldiers firing simultaneously.
The part of an Ink Grenade that creates the poison has been revealed to be a baby Nemacyst.
The link between Nemacysts and Seeders is confusing, neither is seen without the other, meaning Seeders are needed to launch or produce them. The link between the radio jamming abilities is even more confusing, though it could be the Seeders or the Nemacysts using their ink to jam the transmissions. Nemacysts are used as anti-air, and air-to-ground attack units. The are also apparently used as Locust artillery.