A/N: This is a work of fiction using the characters from Harry Potter which is trademarked by J.K. Rowling
Peter sat silently in his chair. Every muscle in his body tensed and his thoughts ran a mile a minute. He felt sweat breaking out all over his body and his hands curled into fists. Peter felt his nails dig into his palms and swore that he felt his skin as it started to break under the pressure. His breathing began to accelerate, and he knew he was panicking. He looked to his left and saw his companions seated beside him however they didn't look nearly as nervous as he did.
Peter never understood how they could stay so calm. He could feel an uncomfortable churning in his belly. Sweat beaded on his brow and he knew if he looked in the mirror his complexion would be whiter than Peeves.
Peter gulped and fidgeted when his gaze locked with glaring grey eyes. His breath stuttered in his chest and he tried desperately to quell the fear he felt.
Peter watched helplessly as Professor McGonagall paced across the classroom pausing every few minutes to glare and him and his friends. He knew they were in trouble. He knew they were going to get caught.
Professor McGonagall finally stopped pacing and stood glaring at them. She locked eyes with each student individually before she opened her mouth to reprimand them and only the roar of a lion was heard. Peter heard the muffled chuckles of his friends that immediately cut off when the Professor's glare was directed their way.
McGonagall's gaze focused back on Peter and when he locked eyes with the professor he could feel himself slowly start to break apart. He could feel the burn of his friends glare but he couldn't hold it in any longer. To be honest he lasted much longer than he originally anticipated.
The words bubbled up without his control and no matter how valiantly he tried they came spewing out, "It was us Professor. Remus and I kept watch while James and Sirius stole your tin of shortbread biscuits. They replaced them with tainted one. I'm sorry. Have mercy!" he whimpered and looked down at his shoes.
After his rushed confession the classroom was silent and only Peter's panicked breathing could be heard. Peter fidgeted in his seat and finally looked up. All he could see was the pleased look on his Professor's face.
When Peter looked to his left he saw the looks of anger and betrayal that clouded their eyes and he hung his head in shame.
After a few second he heard the groans from his friends and he looked up to see what had caused them and he caught sight of the words, 'DETENTION: TWO WEEKS' as they hovered in the air in front of them.
"Dammit Peter!" Sirius and James yelled and Peter slumped down in his chairs and avoided their looks.
Prompt #1: Peter Pettigrew betrays his friends
Prompt #2: McGonagall's tin of shortbread biscuits