The movie sucked, no one contests that, but fans of the TV series "Buffy the Vampire Slayer" may be surprised to learn that the "Vamp" look, the face of a Vampire revealing their true nature, was based on a very real, very tragic genetic disorder.
In the Buffy universe, Vampires have two faces. The first is a "normal" human face, one that looks like everyone else. The other face, the one they reveal only when about to make a kill, is intended to be far more disturbing.
The forehead wrinkles like a Klingon from Star Trek. The makeup makes the eyes look farther apart. The nose flattens and broadens, revealing enlarged nostrils.
Here are a couple of samples:


Nice and spooky, isn't it?
Let me show you another set of images, this time a "Before" and "After" picture.

What does that look like to you? If you add just a few wrinkles to the left hand image you get a typical "Vampire" transformation from "Buffy the Vampire Slayer." Can't you just imagine him opening his mouth to reveal a set of fangs?
The thing is, this isn't an image from a TV Horror sitcom. The image is from the Cranial Facial Center. Here's the text that goes with the image:
Orbital Hypertelorism
The left hand "Before" Image: Fifteen year old male born with incomplete midline facial cleft causing increased distance between eyes.
The Right Hand "After" image: Postoperative result after extracranial reconstruction of hypertelorism
Josh Wheadon based the villains for Buffy the Vampire Slayer" on victims of Orbital Hypertelorism, a tragic disorder that causes disfigurement and prejudice against its victims. I spent several hours looking at images of victims of this birth defect and comparing them to the vampires from "Buffy the Vampire Slayer." The similarities are shocking and consistent. Every vampire "look", every Vampire face has a corollary in Orbital Hypertelorism. It's as if the makeup artists had a clinical diagnosis book beside them as they designed the vampire face for each actor and actress.
The physical evidence is undeniable. The motivation is more mysterious. Why was a known genetic disorder used as the template for a monster? Was Wheadon hoping to increase the horror of these faces by creating ones that were, through the course of nature, possible? Did he once see victims of this disease and chose to act out his reaction to them by using them as monsters? Did he have a negative experience with someone who had this disorder and chose to vent that hatred through television?
Perhaps his motivation is even more subtle. He's often spoken of "Buffy" as being set high school because the politics and behavior of high school students made the presence of supernatural monsters almost believable. Perhaps this is just a case of the high school bully making fun of the disabled kids by parodying them in a school play. Think about it. A group of athletic, attractive and popular kids spend their days (and nights) destroying the disfigured and unpopular.
Buffy was, after all, a wealthy, cute, blond cheerleader. What's more stereotypically popular than that?