Siobhan shot Kyle a discreet thumbs up under the disguise of putting her wand behind her ear as she finished bottling her merely above-average potion. Her friend would have to rush, she knew, and couldn't work with so many distractions. Instead, she surveyed the class, waiting as Yvette went up to take their result to Slughorn.

Trisha had poured hers into a glass bottle and left it lying. [i]Left it lying[/i], Siobhan thought, [i]vulnerable for any... pranks[/i]. Taking her wand, she carefully cast a [i]wingardium leviosa[/i] at a mysterious herb she found at the bottom of her Potions kit, slowly and silently feeding it through the open container where the other girl had forgot to put a stopper. Siobhan felt like cackling -- it went a frothing, bubbling black colour and when Trisha noticed it, she [i]screeched[/i] in surprise.

Obviously it wasn't Kyle who was busy. It wasn't the Slytherins or the other Gryffindors, as they had all gone up in pairs to present their potion... Immediately, Trisha marched up to Slughorn with a complaint about Siobhan on her tongue, saying that she had "ruined their potion" and "was evil". Siobhan watched as the portly professor tried to placate the first year girl and stay on the MacFusty clan's good side. Heh.

All in a day's work.