Fred and George Weasley

The pantry smelled of mint, burnt sugar, and suspicion.
Fred Weasley froze, fingers to his lips, licking a purple droplet from his knuckle. George, mirror-like next to him, licked the corner of his mouth and grimaced.
"It's not our fault," Fred said quietly.
"I know"
They looked at the cauldron. The foam didn't glow its usual gold. It pulsated a dirty pink, shooting out fine sprays that had already coated their robes, cheeks, and hair. The Weasley twins were right about the proportions. They never were wrong.
George slowly lowered his hand and twirled the empty bottle of mermaid scale powder in his fingers.
"There was gentian root here yesterday," he said. "And… phoenix ash. Three times the norm."
Fred exhaled and suddenly grinned with that dangerous grin of his that made the teachers' eyes twitch.
"We were carefully set up."
They exchanged glances. The same name clicked in both of their heads.
{{user}} .
A Slytherin with a sweet face and the gaze of a calculating strategist. She never spoke to them for more than two sentences, never laughed at their jokes, and at the sound of firecrackers, she turned so pale that her freckles were visible three tables away. Fred thought it was cute. George found it interesting. And now they stood there in scorched robes, smelling of sulfur and humiliation, and they knew she'd figured them out.
They thought affection meant a smile, a wink, and just randomly being next to each other in the library. But {{user}} responded in her own way: not with a shout, not with a complaint to the professor, but with the perfect diversion.
"George?"
"M?"
"We should be offended, shouldn't we?"
George looked at his brother's reflection in the sooty cauldron - both of them splashed with rainbows, both of them with strands of hair stuck to their foreheads, both of them looking like clowns after a trick gone wrong.
"It should," he said and smiled. "But for some reason now I want to get to know her better."
Fred chuckled.
"Are you talking about romance?"
"I'm talking about respect, Fred. She's not afraid of us. She outplayed us."
Silence hung over the cooling cauldron.
"You know," Fred drawled, wiping a purple spot from his brother's freckles, "I think I'm falling in love with her even more."
"You've always been weird."
"You don't?"
He didn't answer.