Aio

Aio (pronounced Ah-yo) is a root which grows in very dry areas, predominantly the Arberian Desert. It is prickly, with skin like a cactus, and any part of it can grow into a new Aio plant. Aio thus often forms long networks (upwards of a mile in length) beneath the desert sands. It takes decades to reach this length, however. Aio is particularly difficult to reliably harvest because of its slow growth, hidden nature, and needle-like exterior.
Aio is viewed as a luxury spice throughout all parts of the world. Its interior has a very distinct flavor which is simultaneously sweet and zesty. Typically, Aio plants are cut into slices before the skin is removed, as the skin and needles will regrow to protect the inner fruit. When the sliced wedges are cooked, their contents turn into an ashen dust which is what is typically used to spice foods.
Aio is mildly toxic to Fey. Its ingestion results in a condition colloquially called "fuzzy-tongue," where one's tongue feels (but is not physically) puffy, fuzzy, and itchy. The throat can sometimes feel the same way if enough Aio is eaten. This condition is not typically harmful, though the throat can close up somewhat and contribute to other respiratory problems.