Ellerie's Aura of Song

An aura of musical notes emanates up to 30 feet from you. Choose a number of creatures within 30 feet of you, up to your Charisma modifier (minimum of one). Until the spell ends, the first attack made against each chosen creature on a turn is made with disadvantage, as the aura’s harmonies disrupt your foes’ accuracy.

At a higher level

At every level higher, the caster can add up to one more creature to the spell.