La Sirena- Half woman- Half Snake- Source: Sandro Halpo
In order to preserve and share Belizean Folklore the following text is from Characters and Caricatures in Belizean Folklore: By Belize UNESCO Commission 1991.
“When she lures you, she takes you to the lonely road where she leaves for lost all those who fall under her spell.” ‘sic’ ( I think they were going for, She leaves all those who fall under her spell lost.)
La Siguanaba or La Sirena.
“A weeping spirit associated with water and streams, La Sirena has long, black hair and is fully clothed in white. Stories of La Siguanaba in some Belizean communities indicate that she is the same character as La Sirena. The word Sirena translates literally from the Spanish as mermaid, whose half-woman, half-fish body is comparable to the half-woman, half-snake body of La Sirena. Her face, which may sometimes be hidden, is described by some as beautiful and by others as ugly. Some versions even say she is hiding a horse’s face or skull underneath the cloth she wears over her head.
La Sirena.
La Sirena is believed to be the spirit of an evil woman who grew tired of her child and threw it into a stream to drown. She now sits near the river at night, and many people fear seeing her, for it may be an omen of their death. She will sometimes carry children off for three days, and when she returns them, they are disoriented and unable to function normally for several days. Most often, however, she chooses men who are roaming late at night, especially drunks, as her victims. She impersonates men’s sweethearts and leads them down a path from which it is difficult to return, and those who search for a way out become frustrated and delirious.
La Sirena and her child. Source: Howstuffworks
One Maya legend about La Sirena tells that she was created by the supreme evil being from objects in the environment. When he was ready to put hair on her, his eyes rested on a nearby tree and he used its branches to form her hair. The following story is often attached to this legend.
La Sirena- Source: Deborah Duflon
A young villager had been drinking with his friends all day and was returning home on horseback. His journey took him through some forested areas, and in one such area, an attractive woman suddenly appeared before him. He dismounted in order to approach her, and as he came nearer, she tried to embrace him. He then realized that she was the enchantress La Sirena spoken of in his village, but he was under her spell already and was being compelled to follow her. He tried to stop himself from going further by grabbing on to the branches of a tree and was immediately released from her spell. The tree had held on to was the same one used to make La Sirena’s hair, and legend has it that pulling on the branches of the tree makes her feel as if someone is pulling her hair.
La Sirena. Source
Among the Garinagu, stories are told of the Agayuma, who resides near the water, and seduces men with her long, silken hair and shapely body, whose form she can change to resemble various water creatures. Agayuma’s victims are plagued by dreams of her, and only a special item given to them by the buye or medicine man will keep the dreams away. If, however, no precautions are taken, the victims waste away and die.
Some years ago, in the village of Barranco, five girls told of their encounter with the Agayuma during the dry season. They had all gone to fetch water from the pond, and while there, they saw an apparition which each reported as a fair woman, dressed in full white. She sat near the edge of the pond, from where she rose floating toward the bush, disappearing into the trees. They thought they had seen the Blessed Virgin Mary, but the elders of the village heard the story and concluded that the girls had, in fact, seen the Agayuma.”
La Sirena: Described sometimes as having a horses face. Source: Octophiliac
Lower Dover Field Journal 
