There are a ton of stars who've dressed up in awesome Halloween costumes this year, but how many of them took it up another notch and actually sang with their getup? We'll tell you who: Kelly Clarkson. On Friday, the singer uploaded a Facebook video of herself singing an amazing a cappella cover of Sia's "Chandelier." To make matters even better, Kelly donned Sia's signature blond wig and joked, "I don't know how she does this because, you know, she can't see." Trust us, you'll want to watch this.