Doomspeak( Champions of Ruin, p. 20)
You can demoralize an enemy with horrible condemnations and grim portents of impending doom.
You can spend one of your bardic music uses to utter a string of crass and appalling epithets and curses at one enemy within 120 feet. The intended target must be able to hear and comprehend your damning remarks. A target that fails a Will save (DC 10 + your character level + your Cha modifier) is cursed with a -10 penalty on attack rolls, saves, ability checks, and skill checks for 1 round. This is a supernatural, necromantic effect.