After a sixth year prank, Dumbledore is determined to watch Snape for any ill effects. For all his apparent wisdom, however, not even he could have foreseen the extent of those effects. Spoilers ahoy, and AU after HBP.
Snape has an unwelcome nighttime visitor.
Severus Snape may be bitter, but he has his reasons. Spoilers for OotP.
Completed novel fanfic: Professor Lupin happens upon a supposed Muggle who has some intriguing interests and powers, only to find out she may not be such a Muggle after all. Snape features prominently; Dumbledore, McGonagall, and Sirius Black also appear.
On that fateful Halloween night in 1981, two heroes died and another was born. But what events transpired to make Voldemort's attack possible? Told through the eyes of the traitor...
While still alive they did divide their favorites from the throng, yet how to pick the worthy ones when they were dead and gone? 'Twas Gryffindor who found the way, he whipped me off his head. The founders put some brains in me so I could choose instead!
Due to an accident in Potions class, Neville Longbottom creates a dangerously powerful love potion, and Professor Snape is forced to rid the school of the potion. Unfortunately, he can't do anything about the effects. Please R&R!