SSHP Severus Snape thought he would die in the war. So did Harry Potter. Three months later, they're both alive and ready to return to Hogwarts for a quiet year, but when they encounter a strange potion, it has them swapping bodies with no known cure.

Not once did the face of the devil show fear. Not when he stormed into class with every intention of singling the boy out and revealing him to be just like his father. Striking green eyes met his in a steady gaze, made him feel, and that made him angry.