Mavka, vodyanikha, joker, tickler, vila, undine, or simply speaking, a mermaid, but in Slavic mythology.

• this is a harmful spirit that appears in the summer in the form of a long-haired woman in a cereal field, in a forest, near water, capable of tickling a person to death or drowning in water. The East Slavic term "mermaid" is associated with the ancient Russian name of the pagan spring holiday of Rusalia.

Most often it is believed that unbaptized children, drowned girls, girls who died before marriage, as well as those who were born or died on Trinity week, become mermaids. In western Polissya, there is a legend about how the father of a deceased bride tied her body to a post and thus “married” her so that she would not become a mermaid. In other beliefs, she is considered to be a werewolf. And it is also believed that the Slavic mermaids are friends of the Vodyanoy.

In Polissya, the word mermaid is often used in relation to the dead in general or even to specific dead residents of their villages.