[In any other circumstance, seeing Longbottom so riled up would have had Severus feeling triumphant and smug. This, however, just makes him feel uneasy. Cornered. Cornered by Longbottom, of all pathetic, useless people.

His nostrils flare angrily and his lips twist into a dangerously thin line.]

That's your "proof", is it?

[A pointed pause.]

And what other startling revelations of proof do you have at hand? I suppose bothering to actually question any of the students who attend my school hasn't crossed your dimwitted mind. Why would it? You so clearly have a far better understanding of everything you're accusing me of than I.