When you cast a spell that requires the target to make a saving throw while wielding this magically-attuned instrument, you may roll one of your Bardic Inspiration die, and subtract the number rolled from the target's saving throw. If the spell targets multiple creatures, you must expend one Bardic Inspiration die per target you wish to affect.

Additionally, the bard attuned to this instrument knows the cantrip vicious mockery if they do not already, and any creature that succeeds their saving throw against vicious mockery still takes damage from the spell, but suffers no other effects.

Notes: a bard, Buff, Debuff, Instrument