Feral Potatoes

Sinister Spuds or more commonly called Feral Potatoes are found all across Timeuria, but most commonly within the nation of Stoze. They are infected with a blight that some believe to be a curse on the land itself. They originally got their name when the first people to eat them became infected after consumption. They became mad, spouting nonsense and lost all sense of the world around them and died very quickly, usually only a matter of days afterwards. Many attempts to cure diseased individuals were made but with minimal positive outcomes. Only a handful of people to ingest this savage spud survived. Its appearance is near identical to that of a normal potato, except for small black spores that form inside. This makes it difficult to determine if a potato is dangerous or not and as a result, any questionable ones are immediately disposed of far from the other crops.
Eventually this caught the attention of alchemists interested in its deadly properties. They began to experiment with them and eventually were able to develop a method for extracting the diseased sections and turning them into potent poisons. In its most concentrated form it results in immediate excruciatingly painful convulsing, loss of memory and death within a few hours. This poison is heavily guarded by those who create it as it can be disastrous if it were to fall into the wrong hands.