A žaltys ([ʒɐlʲˈtʲǐːs], literally: grass snake) is a household spirit in the Lithuanian mythology. As sacred animal of the sun goddess Saulė, it is a guardian of the home and a symbol of fertility. People used to keep it as a pet by the stove or other special area of the house, believing that it would bring good harvest and wealth. Killing žaltys was said to bring great misfortunes upon the household. If žaltys was found in the field, people gave it milk attempting to befriend the creature and make it a sacred household pet.
References
Žaltys Wikipedia(Text) CC BY-SA