Now Harry has been studying for an important test in Alchemy for a while now: thankfully it is a practical test that will require him to know the ingredients and procedures for potions and the like without relying on books too much than a written exam, so he wants to get onto it and prepare for it.

But his Alchemy studying comes to a major screeching halt when he overhears a pile of trash falling apart and water rushing in. Confused and terrified, he runs out to the trash pile, blinks his eyes numerous times, and looks at it in shock. Can someone explain to him what just happened while he was busy studying?