That day, Harry was having tea in Professor Lupin's office while Professor Lupin explained the water demon they would be studying in the next lesson.
Harry took a sip of tea, but couldn't help asking, "Professor, why won't you let me deal with him?"
"Harry, I'm afraid you'll turn the Boggart into Voldemort or a Dementor right there in class. You know that would cause a little too much panic."
"Knock, knock, knock."
Snape knocked and came in, carrying a steaming goblet.
"Thanks, Severus."
"I suggest you drink it straightaway, Lupin. I've still got a whole cauldron of it."
Perhaps because Harry was still there, Snape left without saying much more.
Seeing Harry's curious expression, Lupin smiled and explained, "Professor Snape is good at brewing potions. I'm not very good at making them, and this one is especially complicated—and very bitter."
"What's wrong with you?"
"Don't worry, Harry. I've just been feeling a little unwell. This is the only potion that helps, and I'm lucky I ran into Snape. There aren't many wizards who can brew it these days."
After sitting for a little while longer, Harry decided to head back to the common room. But he found a crowd gathered outside it, with no one going in.
He went over to look and saw that the Fat Lady had vanished from her portrait. The painting had been slashed viciously; scraps of canvas lay scattered on the floor, and a large section had been torn away.
Percy hurriedly sent someone to inform Dumbledore. Hermione grabbed Bing Huan's arm in shock. "Oh my God, what happened?"
"It looks like the work of a beast."
In the end, they found the Fat Lady hiding in a landscape painting.
She trembled as she answered Dumbledore's questions. "It was Sirius Black. I just wouldn't