She is a powerful necromancer; while she is surveying dead bodies in a battlefield it is noted that "If she had tried to raise up the entire army on the field to return to war, the laws of Erebus would have yielded, and a host—pulled from the Stygian Avernus by her terrible power—would have gone to war." It is for this reason that she is sought by Pompey the Great's son, Sextus Pompeius. He wants her to perform a necromantic rite so that he might be able to learn the outcome of the Battle of Pharsalus. Erichtho complies and wanders amidst a battlefield to seek out a cadaver with "uninjured tissues of a stiffened lung". She cleans the corpse's organs, and fills the body with a potion (consisting of, among other things, a mixture of warm blood, "lunar poison", and "everything that nature wickedly bears") so as to bring the dead body back to life. The spirit is summoned, but, at first, refuses to return to its old body. She then promptly threatens the entire universe by promising to summon "that god at whose dread name earth trembles". Immediately following this outburst, the corpse is reanimated and offers a bleak description of a civil war in the underworld, as well as a rather ambiguous (at least, to Sextus Pompeius) prophecy about the fate that lies in store for Pompey and his kin.