To fight the Tyranids by traditional means is to foolishly move a beach one grain at a time.
— Inquisitor Kryptman, Warhammer 40,000
The onrushing hordes of a Tyranid swarm are a terrible sight to behold. Scuttling Termagaunts rub shoulders with deadly Genestealers, huge Carnifexes lumber forward beside tall Tyranid Warriors in an avalanche of rattling armour plates, glittering fangs and gigantic claws. Discipline is hard to maintain against such a horrifying foe as many men are driven mad with despair or frozen with terror at their approach.
It is well known that destroying the more intelligent creatures in the swarm is essential to stop a Tyranid advance. Training in recognition and fire discipline is of some help in identifying the best targets, but the chaos and confusion of the battlefield make it difficult for troops to pick out their targets amidst the swarming mass of creatures. Ultimately is has proven best to direct fire at the largest Tyranids in sight and pray to the Emperor that some of them are the leaders.
— Inquisitor Angmar - "Halting the Abomination", Warhammer 40,000
The blasphemy of the Tyranids is such that there is only one acceptable solution - Extermination. There can only be two side in such a fight- choose carefully, lest you and I find ourselves on different sides.
— Reclusiarch Cassius of the Ultramarines, Warhammer 40,000
Another wave inbound! Man the walls!
— Castellan Tronktom‚Äôs Last Stand, Laveria Prime, Warhammer 40,000
The bugs are not like us. The Pseudo-Arachnids arenít even like spiders. They are arthropods who happen to look like a madmanís conception of a giant intelligent spider, but their organization, psychological and economic, is more like that of ants or termites; they are communal entities, the ultimate dictatorship of the hive.