This type of song can be used in the last scene of real Little Mermaid scene. By real, I mean the original Anderson story where the mermaid commits suicide by jumping in sea. It's also very fitting for the scene when she tries to kill the prince but hesitates.
.....And so Princess Gabriella, adorned in her tattered gown covered in blood splatter, dances with the upper torso of Kevin, Her handsome Prince...Long dead, Kissing him tenderly, giggling at a joke only she can hear him tell her. A few screams can still be heard echoing through the ballroom as she waltzes with care and grace around the bodies on the floor. She is truly happy in this moment...and after all....doesn't every Princess deserve a happy ending?