The last time Marina Abramović made a work with “Balkan” in its title, it involved her scrubbing the blood off thousands of cow bones for four days straight. The year was 1997, and the bones of her homeland, the onetime Yugoslavia, would never be clean. Balkan Erotic Epic points further back. This “orgy of dancing, grieving, screaming, desiring bodies,” as the art magazine Frieze has it, evokes the folk customs that the 79-year-old Serbian’s grandmother—her first and better mother—imparted to her as a young child. They include such unlikely wisdom as how to reveal your vagina to the gods to stop the rain. “I didn’t invent any of them,” Abramović insists. With 30 performers (dancers, musicians, singers, life-size puppets) and just as many behind-the-scene operators (choreographers, composers, costume designers, videographers), Balkan Erotic Epic proves at once excessive and exact, surreal and autobiographical. It is, Abramović has said, “my heart, my guts.” —Apollinaire Scherr