Leshy

Leshy (, in English sometimes spelled Leshii or Leszi) is a mythical creature that appears in Slavic mythology. It is also the subject in “The Witcher” Saga written by Andrzej Sapkowski.
A Leshy is male and human in shape and can assume any form. A Leshy can change in size and height. In some accounts, the leshy is described as having a wife ("leshachikha/leszachka/lesovikha") and children ("leshonki/leszonky"). Because he is known to lead travelers astray and abduct children, which he shares with Chort, or "The Black One," the Leshy is believed by some to be evil. Others view him as more of a temperamental being like a fairy.
In mythology.
In beliefs of Slavic people, Leshy appears in forests. He’s kind of a protector of the forest and everything that lives in it. His natural form looks like a human but he can easily shapeshift into any plant or animal. A Leshy has long hair and beard made of grass. It can appear in human shape or can change in size from a tall tree to a single blade of grass.
"The Witcher" books and games.
In Sapkowski's "The Witcher" (Polish: Wiedźmin), a leshy is a monster that lives in the forest. It has been described as something that "lives only to kill". When they kill something or a human, they do not leave much for the carrion eaters.
In the "Witcher" video game, a Leshy is a highly intelligent monster that lives in forest. Common people thinks that he is like a friendly sentinel of the forest. That is not true. This is a very dangerous creature that hunts down whatever lives and moves. It can polymorph. In its primary form the creature looks like a bear and wildcat combined. It has long fangs and sharp claws. When it hunts it lurks among the tree branches and then jumps on its victims. Usually it eats its victim whole.