Bisexual, Vampire Teen Wizards

AKA, BVTW Syndrome.
The most common example, is My Immortal, which is considered to be the worst fanfiction ever produced and, may have in fact, existed since the dawn of time. Some believe it to be one of Nyarlathotep's 999 forms.
It is also commonplace on free form roleplaying message boards.

The disturbingly common practice of writing Harry Potter-based fanfiction or creating HP-based characters that are, for purposes of the female writer's fantasy, bisexual for other "hawt Hogwarts guys" and, on occasion, situationally "hawt" for the writer's alter ego, female main character.

...Oh and they're also VAMPIRES.

Bad HP slash writers (oxymoron?) LOVE vampires.

People who suffer from BVTW Syndrome:

-Likes-
Vampires
Any combination of: Ron, Harry, Draco and Snape fucking in the Forbidden Forest.
Goth anything
Hot Topic
F-bomb dropping Dumbledore
Gun toting Voldemorts

-Dislikes-
Spelling
Hogwart's boarding school Dress Code.
Vampires that have fangs and burn in sunlight.
Magic classes.
Quidditch
Writing anything with even the remotest of semblance, to the characters and stories that these fanfics are based on.