the_debt_of_time

Sirius, James, and Remus all shared a look. Peter looked down at the floor, utterly
devastated. Mia caught the expressions and quirked an eyebrow, figuring that the boys had
at least begun their Animagus training.
"All right, now, when I let this boggart out and it turns into your fear, I want you
to aim your wand and envision something funny in your mind. See it very clearly, focus,
and say, 'Riddkulus,' all right?"
Slowly the class moved away from Mary, but none faster than Mia, Remus, and
Sirius who stood with their backs pressed tightly against the rear wall of the classroom.
Professor Prewett flicked his wand, and the latch keeping the boggart in the trunk
opened. The lid kicked backward with a bang! A very large rat with small, watery eyes and
long, yellow front teeth crept out. It was the size of a dog. It turned and sniffed toward
Mary, who looked petrified.
"Riddikulus!" she finally shouted, watching as a large mousetrap appeared beneath
the rat and sprung forward.
Peter gave a loud yelp and turned to vomit in a nearby dustbin.
Mia grinned vindictively at the sight but turned her attention back to the rat, which
had turned into a rubber toy rat that squeaked as the metal trap continuously squeezed it.
"Well done!" Professor Prewett said with a grin, and Mary smiled. "Everyone form
a line!"
They all did, save for the three frightened Gryffindors at the back of the room.
The professor gestured to Alice. "Miss Brown!"
There was a loud crack, and where the rubber rat had once sat now stood a large
cockroach towering over young Alice.
"Riddikulus!"
The cockroach slipped on a banana peel that had appeared at its feet and fell
backward onto its back, unable to right itself.
"Mr Pettigrew!"
Peter slowly stepped forward, nervously holding his wand in hand. With a crack,
the upturned cockroach turned into a large cat that paced back and forth across the room,
stalking with its yellow eyes turned on Peter, licking its jaws.
"Riddikulus!"