Kristina

“Neville had somehow managed to melt Seamus’s cauldron into a twisted blob, and their potion was seeping across the stone floor, burning holes in people’s shoes. Within seconds, the whole class was standing on their stools while Neville, who had been drenched in the potion when the cauldron collapsed, moaned in pain as angry red boils sprang up all over his arms and legs. “Idiot boy!” snarled Snape, clearing the spilled potion away with one wave of his wand. “I suppose you added the porcupine quills before taking the cauldron off the fire?” Neville whimpered as boils started to pop up all over his nose.”
― J.K. Rowling, Harry Potter and the Philosopher's Stone