"It was just a thought."  Snape smirked at her.  "Yes, it looks like an accident with Polyjuice, Poppy.  I’d guess she plucked cat hairs off the robe of whomever she was attempting to impersonate, rather than human hairs.  Polyjuice is not meant for animal transformations, and you can see for yourself why. I think it’s fairly safe to treat it as a Polyjuice accident."