Buffy, the Vampire Slayer: Inca Mummy Girl

Buffy hosts a foreign exchange student named Ampata, who she believes to be a male, but is surprised to learn he is actually a female whose identity has been usurped by an ancient Incan mummy princess. She needs bodies to live, and when Xander asks Ampata to a school dance, he becomes her next potential victim. Willow pines for Xander, but all the while, a student named Oz is becoming smitten with her.