The Iara are beautiful spirits who sing enchanting, siren-like songs to lure men into the jungle. Once a Iara has trapped her victim, she shapeshifts into a snake with red eyes and attacks, leaving the man’s body by water. The Iara are thought to have been women who died violently or outside of the Catholic Church, and are doomer forever to inhabit the jungle as a vampiric spirit. (Encyclopedia of Spirits and Ghosts in World Mythology by Theresa Bane, pgs.74-75) Other tales represent the Iara as more benevolent creature living in lakes and rivers, waiting for a man to lure under water to live with her. Once she has taken him underwater, the pair usually falls in love and she cares for him until he dies, as the Iara are immortal. (http://www.realmermaids.net/mermaid-legends/iara-mermaid/)