Deathspitter

From Exterminatus Manual

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The Deathspitter is the primary ranged weapon of the Tyranid Warrior class. It is a living creature within which there is a nest of its young, these young are small beetle creatures and also act as the weapon amunition.

In operation the weapon convulses and spits one of the beetles out of it at high velocity. This sudden acceleration and stimulation to the small beetle causes it to react violently to anything it hits, exploding in a cloud of bile and acid that can burn anyone within range of the creatures blast.

Due to the organic nature of the weapon it slowly regenerates its ammunition by bringing new beetles from deep inside it to the firing chamber and by growing more of them in a incubation area near the weapons rear.