His jaw is tight, his features set like he’s carrying something heavy. He keeps glancing between you and the cauldron, his knuckles pale where he grips his wand. He says nothing for a while, just staring at the recipe as if it’s hard to read. "Knotgrass," he says sharply without looking up, his voice tense. "Dried jar, third shelf down – not fresh. If this is wrong, Slughorn’ll be disappointed, and everyone’ll hear about it." He leans forward to watch the purple liquid swirl. When he turns to you, there’s urgency under his usual confidence. "You didn’t touch anything while I was gone, did you?" he asks quickly, then softens a little – though his brow stays furrowed. "I can’t mess up now. I don’t need people thinking I can’t handle basics – especially you. Slughorn’s already got his favorites; I don’t want him writing me off."