You hear a scraping at the lock. It's not a key, or at least not one that fits properly. The door swings open, and a geeky looking young man enters.
"I know that janitor Jasper is up to something," he mutters.
A gust of wind blows through the open door, and the parchment flutters off into the darkness. Out of reach, and saving you from accepting that contract.
The man crinkles up his nose in disgust, "He's definitely been working magicks." The youth nods decidedly. "Now I need to take a sample of this brew. He searches his pockets, and then he looks around and reaches for you. You expect you've transformed into a vial, but no you are still a rag. He saw you when he came in, and accepted that you were a rag. He has taken a plastic baggie from his pocket, and is now immersing you in the contract liquid. The ink drenches your rag body. He carefully inserts your potion-laden form into the plastic bag, and heads for the laboratory.
At the lab, you are presented to a prim looking wizardess in a white lab coat. She peers at you over her bifocals.
"The liquid appears to be a binding ink. Used for soul binding contracts and the like," she pronounces firmly. "You say that Jasper brewed this up?"
"Yes, Professor, I only took a small sample. He had a whole cauldron full."
She shakes her head.
"I must report this to the head master. Who knows how many students he'll turn into his slaves this time? I knew simply taking away Jasper's wand and demoting him to janitor wasn't enough." She strides hurriedly out of the lab.
Alone in the room, the young wizard-student holds up the baggy containing you, "Magic Ink, huh? This could be fun."