Prompt: hit by an object

"Mr Weasley, I am sick of your childish antics, please move yourself to the other side of the classroom." McGonagall glared down at the twins who smiled innocently back up at her.

"Which Mr Weasley, Professor?" Fred asked.

"There's two of us!" George chimed in.

"Please specify," the twins said together and the entire class suppressed sniggers as McGonagall's glare intensified. Fred glanced at George, smirked, shrugged, and moved to a seat a few rows behind his brother. McGonagall sighed, rolled her eyes, and moved back to the front of the classroom to continue the lesson.

Fred grinned at his neighbour, and then tore a scrap off his parchment and hastily transfigured it into a tea cosy (it was the first thing to spring to mind) and chucked it at his brother's head. It hit with a larger 'oomph' than Fred was expecting and George glanced over his shoulder, glare evident on his face as he searched for the person who had dared throw a tea cosy, of all things, at him.

"Hey there," Fred mouthed to him when his eyes finally settled on him and George rolled his eyes, tore off a scrap of parchment, scribbled something on it, and then transfigured it into a miniature flamingo (of the plastic kind which could be found in muggle gardens) and threw it back at him when McGonagall wasn't looking, hitting Fred just below his eye.

"Okay, Merlin!" He muttered, transfiguring it back and reading his brother's note which simply told him where he could put that tea cosy. He chuckled lightly and scribbled another suggestion (mainly, up Percy's arse with the stick that had been lodged there for years), transfigured it into a miniature llama – still living, thank you very much – and threw it back. The llama bleated with alarm and McGonagall looked up just as it hit George's ear. Fred sniggered.

"Mr Weasley," she said in an admonishing tone as she marched up to him. "The llama, if you please." He sniggered again as George handed it over, ears flaming as McGonagall transfigured it back to the piece of parchment. She looked up, glaring at George first, and then Fred.

"Mr Weasley - both of you this time - detention."