Droop's Ear Worm

The caster sings a catchy tune that enthralls the target, trapping the song inside their head. As an action, the caster sings or hums a melody, and the target must succeed on a Charisma saving throw. On a failed save, the target cannot focus on spells and cannot maintain concentration (Including spells already cast). As an action on each of the target's turns, they may make an Charisma saving throw to end the effect. On a successful save, the spell has no effect.