So, this is just something I'd love to see in any fanfic where Harry is either superhuman, super strong, or just stronger than average.
Harry looked down at the quill on his desk. "Professor, there's no ink."
The pink toad-erm, professor Umbi-bridge gave a fake, simpering smile. "Oh, you won't be needing ink. Now, I want you to write the line; 'I will not tell lies.'"
Harry blinked, then sat down and picked up the quill. "How many times should I write it?"
"Until the message sinks in."
Shrugging, Harry picked up the quill and began to write. Almost immediately, there was a flare of pain on the back of Harry's hand. Looking, he saw what he had started to write carved into his skin. Glancing up at the pink monstrosity from under his bangs, Harry saw her pleased expression. 'So that's her game.'
Smirking to himself, Harry put the quill back to the parchment and pushed. With a resounding snap, the quill's tip broke off.
"Professor, my quill broke."
Umbit-bridge looked up. "Pardon?"
"My quill broke."
The pink toad stared at the broken quill in shock. "How?" That wasn't possible. Blood quills were supposed to be indestructible. Perhaps it had been faulty? All of her blood quills were family heirlooms several centuries in age after all. She brought out another. "Here you go."
Harry accepted the quill. "Thanks, I-oops!" Harry jerked as he 'accidentally' broke the second quill. "Oh dear, I must not know my own strength."
Umbitc-BRIDGE sat in shock.
Hermione was apoplectic when she saw the wounds on the back of Harry's hand. "Harry! What did that horrible woman do to you!?"
Harry gave a cruel smirk. "Don't worry about it, 'Mione. I gave the toad just as good as I got. I think I broke her."
Umbitch sat motionlessly at her desk, mouth opening and closing uselessly as she stared at the broken remains of irreplaceable blood quills. Now how was she supposed to discipline the lying brat?