Red Blinder (Red Blindah)
Overview
The Red Blinder (mostly spoken "Red Blinda") is a mushroom only cultivated, shipped and used in the Dwarven Brass Dye and the Dumpling Exchange (in their dumplings, doh!) by he dwarven clan of the Stonekin Dwarves.
Cultivating
The problem with the Red Blinder is that this particular mushroom is pretty rare and with its spicy taste a much sought after ingredient, be it for the Dumpling Exchange or the manufacturing of the Dwarven Brass Dye.
Another problem with the Red Blinder is, that it only grows when two different conditions apply: it has to grow in a mineral-rich place and has to be illuminated by the everglowing Blue Chamber Eyes, another mushroom. The light seems to activate something like a defense mechanism from where the Red Blinder got its spicy taste. But when cultivated in the right way the Red Blinder is a speciality on its own.
Dangerous Taste
The taste of a raw Red Blinder is a strange mix of spicy foulness and rich earth. At first, then the substances start to burn off your tastebuds. Aggressively.
Why? Because the spicyness of the Red Blinder is probably a defense mechanism against the shining light of the Blue Chamber Eyes, a bioluminiscent mushroom.
But if you cook it at high temperature for around three to four hours it is... well, no, it is only digestable by most of the dwarves. Well, a Giant or a Troll could manage to digest it, but there are reports that a Troll combusted into fire after eating a Red Blinder after having a steaming hot stew. Maybe it has something to do with it, maybe not; no one had tried it ever since.
The taste of a well-prepared Red Blinder is more of umami than meat or plants, not even like other mushrooms. Depending on the preparation you can have it in a stew in small pieces, dried over an open fire or drained of nearly everything of its liquids to have it in a dumpling.
Usage besides eating
Since the Red Blinder is pretty hard to cultivate because you need two special resources to do it, it is a rare specimen. Besides the Dumpling Exchange & the Dwarven Brass Dye there are only two other methods of using it: as a - very expensive - powder on bolts, arrows or ballista spears and as a ingredient for really a explosive catapult payload.
Fire away!
If you fire the arrow and it hits your target, the powder cause deadly inflammation, sometimes literally, depending on the species and blood-composition. Garladans catch fire, elves scratch themselves to death, humans die screaming.
In terms of a catapult payload the Red Blinder powder is set under pressure in glass bottles. They tend to have a small fuse. When they are fired and break on the target the powder catches fire and explodes in a powerful burst which sometimes can cause stone to collapse.
But as stated above, the mushroom is to expensive to be wasted like this. It is only a desperate measure. Or the initial attack on a high-value target.
Absolutely right!