Master of Discord
From the "Musical Madness" story of Fawcett comic book Ibis the Invincible #3 (Winter 1945). White magician Ibis' sidekick Taia brings home an ancient music box with mystic writing from an antique shop. Taia plays it while Ibis translates the text as a warning not to play it. Why would someone make a music box with a warning not to play it?
Anyway, the diabolic music played by the box summons a bizarre, evil, living G-clef! It kidnaps Taia, and takes her to his home turf, some hellish non-place he calls his Discordant Pit. Ibis defeats the Master of Discord with some amateur harmonica playing, since the creature hates harmony.
They escape and, once home, burn the music box.