Prank Wars

This takes place after the Copper Gauntlet. Everybody has a whole week off to celebrate the Enemy of Death's "death". But the gallery is open only on Saturdays and Sundays. From Monday-Friday everybody even the masters participate in a prank wars. But with the whole school shipping calron is it possible that someone will play a prank that bring them closer.
The magisterium series belongs to Holly Black and Cassandra Clare.