This sap extract from the very exotic Feywild tree known as "Boughs of stillness" is imported in by merchants willing to traverse the treacherous trods. The substance is packed into medicine vials no larger than a test tube. It is mainly used by people in the medical field as a local anesthetic, paralyzing the nerves. However, many adventures find this very useful in imobalizing combatants.
Cost: 80 go per vial. (Imported)
Effect. Treat as any thrown weapon and on a hit, roll a d4, already having called out what limb is denoted by a number. That limb is paralyzed for 30 minutes. If ingested, the creature with be fully paralyzed for 15 minutes . Additionally,roll a 1 on an attack attempt, the substance paralyzes the users throwing arm.
I'd set a DC for the paralyze and allow the target to repeat the save at the beginning/end of the round. Outside of combat I'd set the maximum time to be about a minute. As far as roll a 1d4 and pick a limb, there aren't 'called shots' in DnD 5e and the reason for that is most likely for simplicity's sake. For me as a DM I like that because if my PCs can start cutting off arms off enemies, why the hell as a DM would my enemies not do the same, and it puts me in a situation I'd rather not be in. Otherwise I like the flavor.
Right on man, good feedback. I figured the DC would be 16 with saves at the end of turn. I also thought of making larger pots for a splash effect. As to the called shots, it's a fast and loose thing. It'd be just as easy to do percentage dice and go by 25's, predefined. Thanks man, this is why it's awesome to be in this community. Helpful.