It began with your quill turning purple.

You hadn’t even noticed it at first. You were midway through your Transfiguration essay when Hermione suddenly paused beside you in the library.

“…Why is your ink lavender?” she asked.

You looked down, blinked, and then stared in horror as your neat handwriting slowly shifted from black to bright, sparkling purple.

“HERMIONE.”

She froze. Then very slowly, a smile tugged at the corner of her mouth. “What?”

“You enchanted my quill!”

“I merely adjusted the pigmentation charm,” she said innocently. “For scientific observation.”

You leaned closer. “You did it on purpose.”

She tried to look serious. Failed. “All right, yes. I did. But it was harmless.”

You narrowed your eyes. “This means war.”

She laughed. “You wouldn’t dare.”

Oh, you dared.

The next morning, Hermione walked into the Great Hall and confidently sat down with her toast—only for it to let out a tiny squeak when she picked it up.

She froze.

Ron choked on his juice laughing. Harry covered his mouth. The toast squeaked again.

Hermione slowly turned her head and looked straight at you across the room.

Her eyes narrowed. “You did not.”