Lovecraft's Horrors: "Call of the Cthulhu" World.

As an action, you can splash the contents of this flask onto a creature within 5 feet of you or throw it up to 20 feet, shattering it on impact. In either case, make a ranged attack against a target creature, treating the holy water as an improvised weapon. If the target is a fiend or undead, it takes 2d6 radiant damage. A cleric or paladin may create holy water by performing a special ritual. The ritual takes 1 hour to perform, uses 25 gp worth of powdered silver, and requires the caster to expend a 1st-level spell slot.