With their cloaks aflutter and their fangs flickering in the moonlight, thousands of vampires will take to the streets tonight.
Along with masquerading witches and warlocks, they'll knock on doors, nosh away at bite-size candy bars or guzzle a beer or two at a friend's party.
But Anshar Seraphim, 28, doesn't have any special Halloween plans and has no intention of throwing on a plastic Dracula suit.
Maybe it's because dressing like a vampire one day a year isn't anything special when it's who you believe you are for all 365 of them.
"My personal belief: Vampirism is an inexplicable part of science that we don't understand yet," Seraphim said. "I don't know if the things that cause it to exist are chemical. When we associate ourselves with the word 'vampire,' we're describing the relationship that we have with the people around us."
As fictional or mythological characters -- from Bram Stoker's count "Dracula" to Anne Rice's Louis to HBO's new cast of bewitching "True Blood" suckers -- society accepts and sometimes celebrates the vampire. But for many people, such as Seraphim, vampirism isn't just a literary genre. It's an identity and a lifestyle. Yes, blood-drinking and all.
And though it may sound incredulous, some experts say that there's a little bit of a vampire in all of us.
The Vampire Metaphor
"The vampire image is sexy because it's a trespass," said Katherine Ramsland, a forensic psychologist and author of "Science of Vampires."
"It's not just kissing, it's biting ... the vampire has the ability to make you want it, even though you're frightened of it."
Cultures all over the world, she said, in some way or another, recognize the life force-sucking character. The "vampire metaphor" most common in the United States is derived from the Romanian Dracula, she said. But in other cultures, vampires are only female or only go after children. Others emerge only after a suicide, rather than after a vampire's bite.
Despite the different ways the metaphor is manifested, certain elements undergird it, regardless of where it appears, she said.
"Whatever comes and depletes you is a vampiric image," Ramsland said. "It's not always blood. It's a human metaphor, a representation of a human dread that's both frightening and exciting."
Attracted to this powerful and sexy image, she said, legions of people around the world have formed subcultures that reflect various parts of the vampire identity.
But there is a continuum of responses to the vampire metaphor that draws in members of this subculture, she said.
For some, it's merely an outlet for creativity and having fun. For others, it seeds a belief that they need the blood or energy of another person or animal to subsist. Unfortunately, in very rare cases, she said, it gives structure to paranoia and delusion.
Regardless of how it's manifested, however, it's a very powerful metaphor, she said.
"People can participate in whatever way they want to," Ramsland said. "Some of us are more the blood drinkers or the victim or the hunter. All of us participate in the metaphor in some manner. ... It allows for so much elasticity."
Coming Out of the Coffin
"Vampirism -- for 99 percent of us -- doesn't mean that we're immortal, that we pop out of a coffin," said Seraphim, who preferred to use the name he chose for himself when he began his journey toward vampirism instead of his legal name.
The computer science student at a northern California college is open and introspective about his identity. His professors, for example, know that he identifies as a vampire. But fearing the consequences that might accompany their decision to "come out of the coffin," he said, many professionals, such as doctors, lawyers and nurses, keep their identities a secret.
This makes the exact size of the vampire community difficult to quantify. The diversity of the community's belief systems and habits only adds to the difficulty, he said.
Such diversity also makes it virtually impossible for one person to speak for the entire group, he said.
For starters, not all real-life vampires drink blood, he said. While "sanguine" vampires say they need to drink human or animal blood to revive themselves, "pranic" vampires say they can simply feed off the energy of other humans. Pranic stems from the Hindu notion of prana, or energy, he added.
Seraphim, a pranic vampire, said that he can draw on the energy of people who are within 25 or 30 feet of him.
When he was younger, Seraphim suffered from intense migraines, he said. When a friend who practiced Reiki attempted to alleviate his pain with the energy-healing practice, Seraphim said he started to think that it was an imbalance of internal energy that was causing his headaches.
"As a 'spiritual diabetic,' I unknowingly stumbled through the varying degrees of my condition," he told ABCNews.com.
Now, when he begins to feel depleted or out of balance, he can either "sip" from the ambient energy of surrounding crowds or eat a "scheduled full meal" from a group of friends who have granted their permission.
Seraphim, who said that he has always thought of himself as an empathetic person, has noticed that in his presence, others' emotions become enhanced. In a sense, he said, this creates a surplus of energy that he can feed from to balance out a deficiency of his own.
Aware of the strong effect he has on others, he said, he is constantly working to control his power. Friends and family tell him that he doesn't hurt them, but they do sometimes admit to feeling more drained, he said. Some say they feel "transparent" around him.
But his identity hasn't harmed his relationships, he stressed. He and his mother are close, and he said he has a diverse collection of friends. Many of them are also vampires and members of House Lost Haven, a close-knit, semiformal group of vampires and "otherkins" who believe that their souls are connected to nonhuman creatures, he said.
But not all of his friends are vampires, and he said he also dates women outside the community.
His girlfriend, Shade, isn't sure if she's a vampire and is exploring the identity, he said. Still, she has been initiated into House Lost Haven.
As a pranic vampire, Seraphim said that he doesn't feel the need to drink blood. But, on a few occasions, he has experimented with it with people, like Shade, whom he trusts, he said..
"I had a drink of someone's blood before and got a positive experience out of it, but I don't need that to survive," he said.
Why the Desire for Blood?
Some vampires cite the so-called Renfield's syndrome, a condition used to describe an obsession to drink blood. (Renfield is the name of the fly-eating character in Bram Stoker's "Dracula.")
But this condition is not recognized in medical literature and is rejected by medical doctors, psychiatrists and psychologists.
"First of all, it absolutely, 100 percent should be discouraged by everybody. The safety issues are gargantuan," said Keith-Thomas Ayoob, an associate professor at the Albert Einstein College of Medicine in New York City.
There's an enormous risk of contracting blood-borne diseases, he said.
Underscoring the dearth of evidence for Renfield's syndrome, author Ramsland said she knows the clinical psychologist who made up the term as a joke.
But in very rare cases, she said, people suffer from clinical vampirism, which is the psychotic delusion that you need blood to survive. Convinced that they need to drink blood, she said, some people cut their own arteries or have killed loved ones.
This condition, she emphasized, is very different from forming a persona around a vampire and participating in a subculture that celebrates it.
Merticus, a 30-year-old "hybrid" vampire who is also a member of the invitation-only service group Voices of the Vampire Community, said he feeds on both energy and blood, adding that his primary feeding method is pranic and tantric-sexual, meaning that he feeds on sexual energy and arousal.
The Atlanta-based antique dealer chose not to disclose his legal name to ABCNews.com.
Although the precise reason for craving blood is unclear, vampires "cannot adequately sustain their own physical, mental or spiritual well-being without the taking of blood or vital life force energy from other sources, often human," he told ABCNews.com.
Sanguine vampires feed by drinking human or animal blood but vary in their experience of blood-hunger, he said. They typically consume an ounce or less of blood at a time, usually no more than once a week. When blood is from human sources, he said, it is consensual and facilitated through verbal or written contracts between vampires and donors.
"The vampire-donor relationship is one of mutual respect and gratification," he said.
"We make every effort to educate ourselves on safe feeding methods, basic anatomy and physiology, first aid, sterilization, disease prevention, and safer sex practices," he told ABCNews.com. "We thoroughly screen donors for both physical and mental health conditions and concerns, as well as advocate [for] frequent updates in testing."
They don't feed from those who are knowingly infected with HIV, hepatitis or other blood-borne diseases, he said. And they avoid those whose physical conditions place them at risk of harm by sanguine or pranic feeding.
The Blood Bond
E. Mark Stern, an independent psychotherapist, professor emeritus at Iona College in New York and a widely published author on psychotherapy, has not studied the vampire subculture specifically but has dealt with a number of people who have claimed vampire tendencies.
He recognizes that there are certainly radical manifestations of the phenomenon, noting that some cults have exploited the blood theme to perpetrate fatal crimes.
But aside from these examples, he said, using blood as a way to bond people to a community is not entirely beyond the mainstream.
For example, taking communion in the Catholic tradition means, metaphorically, receiving the flesh and blood of Christ. Some Orthodox Jews practice a controversial circumcision ritual in which the rabbi performing the circumcision sucks some of the blood from the child's wound to clean it.
But the blood bond also exists outside religion.
"When I was 9, we were buddies forever -- 'blood brothers.' We pricked our fingers, mixed them and sucked them," Stern said. "In that sense, it's a way of binding a community beyond the usual forms of understanding. On a rational basis, you can say 'what the hell are they doing?' But on an instinctive basis, then we're bound much more."
Giving another person a hicky could also be considered a mild form of vampirism. "Bringing blood to the surface [means] you're bound to me by this blood sign," he said.
Although the desire to "possess" a person by drawing their blood can indicate insecurity, he said, the sign of blood means protection, too.
Vampirism certainly comes with extremes, Stern cautioned. But given the elements of vampirelike rituals embraced by cultures all over the world, he said, somewhat tongue-in-cheek, "it's hard to separate out 'vampire.' It sounds great on Halloween, [but] everybody's slightly a vampire."