Sirens were mystical creatures of Grecian origin that resembled fish-like women with tentacled humanoid bodies. Sirens were knownn as Kleptes-Virgo; they took on the shape as beautiful women in order to seduce and then eat virgin human males through the use of a hypnotic song.
In San Francisco, Spike and Xander were seduced by two of these creatures in a bar. They planned on provoking a fight-to-the-death between the two men so they could devour the champion. However, the ghost of Anya Jenkins snapped Xander out of it, allowing Spike to kill two of the sirens.
- "Teacher's Pet" (Only mentioned)
- I Wish, Part Two
- Day Off (or Harmony In My Head)
- Love Dares You, Part Three (Only mentioned)