Harry had to smother an excited gasp at the white mist that had slowly began to seep its way out of the tip of Draco’s wand, filling the air like a plume of solid smoke and emanating a bright glow that forced Harry to squint against it. As Draco continued to cast, mist spread further and further, until it hovered in the air in front of Draco like a shield. Harry found himself grinning.