Black sap

Black Sap is a tarry contraband substance found in Blightshore, harvested from the dark boughs of the death's head willow, and is a powerful intoxicant.

Properties
When smoked or injected directly into the bloodstream, the subject creature cannot be charmed or frightened for 1d6 hours. For each dose consumed, a creature must succeed on a DC 15 Constitution saving throw or become poisoned for 2d4 hours, an effect which is cumulative with multiple doses.