Rasputina is an American band influenced by the Victorian Era and the Steampunk movement.
From their official website:
The Rasputina group has existed for more than 20(0) years. Melora Creager founded it to meet like-minded young women (excellent cellists that wanted to play rock music and wear historical costumery). Although often mistakenly lumped into passing fancies, Rasputina manages to survive and defy categorization by maintaining a child-like delight in music-making alongside a clear & true integrity.
The song "Transylvanian Concubine" is included on their album Thanks For The Ether. It was also included on Buffy The Vampire Slayer: The Album (1999 Television Series)
The song plays in Episode 13 of Season 2 - "Surprise" - in which Buffy is having a rather dark 17th birthday haunted by bad dreams about the vampire Drusilla killing Angel. Meanwhile, in an ironic parallel, Drusilla and Spike are planning a party with "presents" arriving in the form of body parts from which they hope to construct an invincible demon to defeat the Slayer.
Transylvanian Concubine is really the perfect song for Drusilla and plays toward the end of the episode when she demands "more music" and unveils the demon.
In another ironic twist, it is Buffy who becomes the vampire's "concubine" when Angel gives her an Irish Claddagh ring to seal their love, and she sleeps with him. The moment of bliss created with Buffy lifts the gypsy curse from Angel, who suddenly loses his soul and goes back to being an ordinary evil vampire whom Buffy eventually has to kill in a following episode. So . . . happy birthday, Buffy! Not!
And alternate version of the song called "Manson Mix" (as in Marilyn Manson) is below. I prefer the original.