Sharp Tongue

Weapon (rapier), rare (requires attunement by a bard)

You're proficient with this magic weapon while you're attuned to it, and you deal an extra 1d4 psychic damage to any creature you hit with it. If the creature has been been targeted by the vicious mockery spell since the start of your last turn, the psychic damage is increased to 1d6. In addition, while holding the weapon, your spell save DC for any vicious mockery spell you cast is increased by 1, and you can cast the spell as a reaction when a creature that you can see misses you with a melee attack or provokes an opportunity attack from you (rather than making the attack), targeting that creature with the spell.

My words will only be the first thing to cut you down.