Expelliarmus! Ah, vengeance is sweet. How I hoped I'd be the one to catch you. I told...

Professor Snape:
Expelliarmus! Ah, vengeance is sweet. How I hoped I'd be the one to catch you.
[to Lupin]

Professor Snape:
I told Dumbledore you were helping an old friend enter the castle and now here's the proof.
Sirius Black:
Brilliant, Snape - once again you've put your keen and penetrating mind to the task and as usual come to the wrong conclusion. Now if you'll excuse us, Remus and I have some unfinished business to attend to.
Professor Snape:
[raises his wand at Black]
Give me a reason. I beg you.
Professor Lupin:
Severus, don't be a fool...
Sirius Black:
He can't help it. It's habit by now.
Professor Lupin:
Sirius, be quiet!
Sirius Black:
Be quiet yourself, Remus!
Professor Snape:
Listen to you two, quarrelling like an old married couple.
Sirius Black:
Why don't you run along and play with your chemistry set?
Professor Snape:
[puts his wand to Black's throat]
I could do it, you know... But why deny the Dementors? They're so longing to see you.
[Sirius trembles]

Professor Snape:
Do I detect a flicker of fear? Ah, yes. The Dementor's Kiss. One can only imagine what that must be like to endure. It's said to be nearly unbearable to witness, but I'll do my best.

Expelliarmus! Well, well, Sirius. Looking rather ragged, aren't we? Finally, the flesh reflects the madness within. Well, you'd know all about the madness within, wouldn't you? - I found him. - I know. - It's him. - I understand. - Let's kill him! - No! I trusted you! And all this time, you've been his friend. He's a werewolf! That's why he's been missing classes. How long have you known? - Since Professor Snape set the essay. - Well, Hermione. You are the brightest witch of your age I've ever met. Enough talk, Remus! Come on, let's kill him! - Wait! - I did my waiting! Twelve years of it! In Azkaban! Very well. Kill him. But wait one more minute. Harry has the right to know why. I know why. You betrayed my parents. - You're the reason they're dead! - No, it wasn't him. Somebody did betray your parents... ...somebody who, until quite recently, I believed to be dead! - Who was it, then? - Peter Pettigrew! And he's in this room! Right now! Come out, come out, Peter! - Come out, come out and play! - Expelliarmus! Vengeance is sweet. How I hoped I'd be the one to catch you. Severus... I told Dumbledore you were helping a friend into the castle. Here's the proof. Brilliant, Snape. You've put your keen mind to the task and come to the wrong conclusion. If you'll excuse us, Remus and I have business... ...to attend to. - Give me a reason. I beg you! - Don't be a fool. - He can't help it. It's habit. - Be quiet. - Be quiet yourself! You two, quarrelling like an old married couple. Run along and play with your chemistry set! I could do it, you know. But why deny the dementors? They're so longing to see you. Do I detect a flicker of fear? Oh, yes. A Dementor's Kiss. One can only imagine what that must be like. It's said to be nearly unbearable to witness, but I'll do my best.