Defense Against the Dark Arts Classroom

The Defense Against the Dark Arts classroom is one of the most fluid classrooms in Hogwarts history as far as decorations and style. The current room is a conglomeration of all of the years past, with scraps of each previous professor's style hidden, if you know where to look. The most interesting aspect of the classroom is that it has a large tank with a grindylow sitting behind the teacher's desk as a sort of class pet.