Srindym

Non-addictive substance, contact/ingested/injury, very rare
An iridescent, silver liquid, this poison was created by elves millennia ago and was often used by less principled individuals of that race against “lesser” races. Very few individuals know how to make srindym -- or know where the secret caches of it are -- so it’s rare and expensive. 
This poison works by injury, contact, and ingestion. Elves (including drow) are immune to srindym, and half-elves are highly resistant to its effect. Other kinds of creatures quickly become disoriented and stiff-jointed, then lose consciousness for a minute or more.
Srindym acts as a sort of antidote to itself, for a while: No single creature can be affected by a subsequent dose of the stuff for about a day thereafter. Also, repeated exposure to the poison brings with it eventual immunity -- every time an individual is beset with it, the resulting period of unconsciousness is a few seconds shorter, until finally the toxin has no effect on that person ever again. Some of those who employ this poison are not initially aware of this aspect of its makeup, and learn about it only when the target of their attention fails to fall down.

Mechanics & Inner Workings

Initial Effects. After being exposed to srindym, a person has to make a DC 18 Constitution saving throw or become disoriented and confused (treat as the nauseated condition) for 1d4 rounds before falling into unconsciousness for a number of rounds equal to 1d6 multiplied by {10 minus [(the user's CON modifier) + (the number of times the user has ever been exposed to srindym)]}. Half-elves make their saving throw with a DC of 10. If the user's CON modifier added to the number of times they have ever been exposed to srindym adds up to 10, then the person is immune to the drug. This immunity goes away if their CON modifier decreases for any reason.
Secondary Effects. None.
Side Effects. For 24 hours after having been dosed with srindym, whether or not their saving throw was successful, the victim is immune to the drug's effects.
Overdose Effects. None.

Significance

Used on Karl during the party in an attempt to kidnap him. Used on Simone by her Uncle whenever she needed to go see the doctor.

Item type

Drug / Narcotic / Medicine

Rarity

very rare

Raw materials & Components

Making srindym is a closely guarded secret that involves elven blood, moonlight, the casting of multiple spells, and several plant ingredients.