Dianopods

Dianopods or "Intellect Beasts" are a subset of magical creatures native to the Material Plane, known to resemble crabs and feed on the fey matter of refuse intellect, which decomposes within all organic matter, including plants, people, insects, the dirt. Dianopods can live up to hundreds of years, amassing vast wealths of knowledge from feeding on the organic intellects in mulch soil like compost worms. Being able to communicate with Dianopod can grant access to knowledge otherwise potentially unattainable.

Inklings
Inklings, a minor Dianopod species, are so called because they can feed off of one piece of intellect for a long time by digesting it through the ink in their shell. They live in vast populations in the wild, often manifesting leaf-like patterns or coloring patterns as they digest the intellect of plants and animals. People have however harvested them for ages wherever they are found to notate ideas, signify agreements. Alive and dead, they serve as reminders of whatever people have put onto them.

Inklings and larger Dianopods have contributed to the development of language, impression technology, interpretive psychology, religious practice, debt-based economy, and many other cultural shifts.

Intellect Devourers
During the Third Regal and Golden Ages, wizards in Hygard experimented madly with the richly populated Dianopods -- the result of one such experimentation led to the advent of Intellect Devourers: dark and genetically pitiful aberrations bred in captivity with no access to any intellect, making them naturally violent and predatory. They can now be used to harvest intellectual information from prisoners or wipe the brains of enemies. Over centuries, some have escaped into the wild, creating horrid nests in sewers and in rotted places -- being naturally drawn to darkness and unable to harvest energy directly from the natural sources. They feed off the intellect of vermin and in turn replicate much of their behavior.

A neutered intellect devourer is unable to harvest any more information -- forced to subsist on raw intellect in the dirt and air, it learns to survive, living a half-life. Information can still be harvested from it through magic, as it is able to commune directly with a brain without collecting information from it.