Brewed by the dwarves of Redlodge. Also available, I'm sure, in Narcosa...
This dark, red-hued whiskey burns with cold but causes euphoric feelings of foolish bravery. Wight Breath Whiskey is brewed by dwarves in complete darkness and kept in ceramic or black glass bottles. It loses potency in seconds if exposed to direct sunlight.
Drinking a shot of Wight Breath Whiskey inflicts 1d4+1 necrotic damage with no save. The drinker must make a CON save (DC 13) or have his hit point maximum reduced reduced by an amount equal to the damage inflicted. This reduction lasts until the target finishes a long rest. The target dies(!) if this effect reduces his hit point maximum to 0.
Each time the drinker's hit point maximum is reduced, the drinker gains advantage on saving throws to avoid the “frightened” condition for an hour. This effect ends prematurely if the drinker's hit point maximum is returned to normal.