Ten minutes to the end of the class, and a light silver mist was rising above both Draco and Harry’s cauldron. Quite frankly, in Harry’s opinion, it was a miracle that he hadn’t ended up with a flammable grey sludge. It had only been Draco elbowing him to keep him on task that had ensured his success: he’d been distracted by the sight of Umbridge pacing up and down the classroom, peering into the odd cauldron before making a note on her clipboard, and moving away. He’d actually set his own tie on fire, leaning forwards to try and hear her questioning Lavender over the sound of bubbling potions. Draco had not been impressed and had hissed threats under his breath until Harry promised to pay attention.