Brain Collectors. Neh-thalggus are carnivores, but they do not digest humanoid brains they eatï¿1/2rather, these brains lodge in one of several bulbous blisters on the creatureï¿1/2s back and help to increase its intellect. Their brain collections may be a morbid form of currency in their home realm, or the thoughts in these brains may merely be fuel for a dark apotheosis into an even more sinister mature form.