L'Armata Brancaleone di Faerun
Dagger of Venom
Weapon (dagger), rare
You have a +1 bonus to attack rolls and damage rolls for attacks you make with this magic weapon. If you apply poison to the dagger, other than its own poison, its saving throw DC increases by 2.
Once per day, you can use an action to cause thick, black poison to coat the blade. The poison remains for 1 minute or until you hit with an attack using this weapon. When you hit a creature with the poisoned dagger, the target must make a DC 15 Constitution saving throw. On a failed save, the target becomes poisoned for 1 minute and takes 2d10 poison damage.