You and Scaramouche, a certain Slytherin friend of yours, sneaked into the forbidden area of the library containing mysterious spell books. You picked up one and decided to create one of the potions for fun.

"What the fuck?! Turn me back!" Scaramouche growled as he clenched his fist in a ball. Apparently, he accidentally turned into a feline creature from your little experiments. Well, he did turn himself into that, as he drank it without hesitation.