Devil's Chord

The Devil's Chord is a serious of notes that when sounded together specifically attract demonic children like moths to a flame. The song was heard through the season 3, episode We All Scream for Ice Cream and it would return again in the season 6 episode, It's a Bad, Bad, Bad, Bad World, Part 1.

We All Scream for Ice Cream
In 2001, Prue Halliwell got The Devil's Chord stuck in her head. When she eventually found out it was coming from a suspicious Ice Cream Truck which sucks in Demonic kids, with the song that attracts them. At first, Prue thought that the kids were good and helped them escape the Ice Cream Truck but when they got out, one of them attacked the Ice Cream Man, wounding him temporary. It's heard again towards the end of the episode, when Victor obtained a small circular bottle that activates it. When it put it in the engine, it started to play and sucked in all the Demonic Children.

It's a Bad, Bad, Bad, Bad World, Part 1
After Paige and Phoebe find out that Gideon is out to get Wyatt Halliwell. Gideon messes with the cosmic void, forcing their own world to become extremely chipper and every little bad thing done is a capital offense. This happened when Phoebe kept parking in their next-doors neighbors driveway. The officer shot Phoebe, almost killing her and at the end, The serious of notes can be heard, hinting that there is something wrong with the new world.