"So, Trisha," Siobhan said with an evil grin spreading across her face just after her potion (and Yvette's) had been held up to the light by Slughorn and graded. Near perfect, though with the slightly off shade it wouldn't taste particularly pleasant. "It's a real shame what happened to your potion -- are you sure you cleaned out the glassware before you bottled it? That can happen sometimes..." She stopped to wait for the professor to mark Kyle's who would be next.

"Exceptional for the circumstances," Slughorn said cheerfully, nodding to Kyle with a slightly nervous smile. 

Siobhan's grin grew wider though for an entirely different reason; more ammunition. "Looks like even McCarthy did better than you," she continued, careful to stick to polite surnames now that they were not-friends. Trisha was turning red with anger and embarrassment, and although Siobhan felt ever so slightly bad, it was not enough to stop her from playing the villain.