Snape was late for a lesson. This was a rare opportunity, and not one that the Weasley twins were willing to let go by. After… subduing the Slytherins, they set to work, causing much amusement among their fellow Gryffindors.
Five minutes later, the last decorations were ready, and the twins had just sat down when Snape strode in through the door. His eyes scanned the room. And he froze.
"Who. Did. This." He said from between clenched teeth. Fred and George stood, and bowed low.
"That would be us, sir." They said in unison.
"Come." Snape replied and, turning on his heel, strode back out of the classroom. Fred and George shrugged at each other and followed, exiting the dungeon classroom, with its fetching new red and gold décor.