The Siguanaba is said to appear at night by a river or other water source as a beautiful woman, bathing or combing her very long hair. Her face is concealed at first, so the man cannot tell who she is; but the moment the enchanted man draws close, her face is revealed to be that of a horse or a human skull.
She targets men traveling alone at night, especially the unfaithful, the drunken, or the womanizing. She tempts them away from their planned routes and leads them deep into canyons and dark forests until they are lost, and her victims are said to be driven to madness or death from sheer terror.
The spirit is known by different names across the region: La Siguanaba in Guatemala, Ciguanaba in El Salvador, Cigua or La Sucia in Honduras, and Cegua in Costa Rica. The name is traced to the Nahuatl cihuatl, meaning "woman." Functioning as a moral warning against infidelity and drunkenness, the legend is thought to have been spread by Spanish colonists to help regulate indigenous and mestizo populations during the Colonial Period.