Shriek Berries and Shriek Paste

An alchemical substance derived primarily from a thorny, yellow berry, shriek paste causes open wounds it touches to flare up with enormous pain. While the paste doesn't meaningfully contribute to damaging the body, sufferers describe the pain inspired by the paste as an order of magnitude beyond that of the effect of alcohol. Shriek berries are agonizing for the first few seconds after ingestion, but the pain then rapidly fades as the stomach's acids counteract whatever agent causes the agonizing reaction.
Uses:
Shriek Paste is often used by soldiers attempting to disrupt the activity of enemy spellcasters, as the wounds inflicted by the paste are so painful that casters must make a saving throw or literally cry out with involuntary pain as their muscles spasm, ruining any attempt to use magic that round. Wounds receiving more than a trace amount of the paste continue to ache and burn for six to twelve hours afterwards, and while the aftereffect isn't as painful as the initial dose, trying to work through the pain can rapidly wear out a person's willpower and endurance. Victims are at risk of exhausting themselves unless they rest through this period.
Counter to what one might expect, shriek berries can be made into excellent wine, though the process of making said wine requires a vinter of the highest caliber. "Shriek wine," as it's sometimes called, is still quite potent and produces the scream and spasm above if exposed to a wound. The distilling process dilutes it, however, so the wine causes no long-term pain or exhaustion.
Logistics:
The availability of this substance varies highly by region, because the bushes that produce the berries only grow in select climates and don't take root easily elsewhere. The concoction itself is relatively simple, but loses its potency easily if not sealed in a container. Weapons coated with the substance will only deliver it effectively for an hour after its application. Shriek paste is illegal in most civilized areas for private owners, with the berries themselves highly regulated, but in regions where the bushes thrive it's not difficult to locate a bush if one knows how and where they appear.
In Culture:
The paste has a dark history of use in interrogations and punishments, and while using the substance is illegal in most civilized areas, several civilizations reserve it for punishing especially heinous crimes. In areas where the berries are plentiful, abusive parents have been known to threaten to use the paste to keep children in line. A small subculture actually use the paste on themselves, however, either as a kind of dare during an initiation ritual or because they like or feel they deserve intense pain. Some street toughs either use or claim to use the substance, with those unable to afford it sometimes bluffing with lemon juice.

Properties

Material Characteristics

A pale yellow paste with the consistency of porridge.