What is "gello"

In mythology, Gello, also Gyllou, Gylou, or Gillo, is a female demon or revenant who threatens the reproductive cycle by causing infertility, spontaneous abortion, and infant mortality. By the Byzantine era, the gello (; plural γελλούδες gelloudes) had become a type of demonic possession rather than an individual being. Women might be tried for being gelloudes or subjected to exorcism.