the_debt_of_time

"Yes, Mr Lupin?"
Remus puffed out his chest, suddenly in his element. "It's a shape shifter that bases
its form on the fear of others."
Professor Prewett grinned. "Ten points to Gryffindor."
"I've always wanted to see one of these," Remus quietly admitted to Mia, who
beamed up at him proudly.
"Boggarts are usually found in dark spaces. Old dressers and wardrobes, inside
cupboards, or beneath the stairs. This little bugger," the professor said with a chuckle,
kicking the trunk again, "was found by my nephews while they were cleaning out the attic
of a friend's house. I offered to take it off their hands. Now, when I let this creature out of
its cage, what will we see?"
Lily's hand flew up quickly.
"Miss Evans?"
"We don't know, sir. If it takes the form of fear, then it will look differently to all
of us."
"You're almost entirely correct. The boggart deals with individuals. So, it will focus
in on one of you at a time. If you're in a group, such as you are now," Professor Prewett
said, gesturing to the class as a whole, "then it'll confuse the boggart and give you a better
chance of defeating it. But if it keeps its focus easily, then it will conform to your worst
fears, and everyone will be able to see them. Not just you."
Several students paled, Mia included. Something deep down told her that she would
not see Professor McGonagall this time, telling her that she had failed all of her exams.
"The charm that repels a boggart is simple, yet it requires force of mind. You see,
the thing that really finishes a boggart is laughter. What you need to do is force it to assume
a shape that you find amusing. We will practise the charm without wands first. After me,
please... Riddikulus!"
"Riddikulus!"
"Miss Macdonald, will you come and help me in teaching the class how to focus the
charm?" He smiled down at Mary, who slowly moved to the front of the class, staring
down at the closed trunk. "Now, what are you afraid of?"
"Rats," Mary mumbled quietly.