Domovoi-Slavic Mythology

Domovoi

Domovois were a spirits who's taking carre about Slavic's houses. A lot of Slavic used to hope that Domovoi had form of little, hunched man with long beard, others though that he had form of head of household and the minority though that he had form of cat or dog. These spirits were very mean to a people who wasn't take care of their house. For example, if  householder didn't wash the dishes, domovoi were scaring him and were pulling small pranks until someone would do it. A domovoi was also an oracle. If that spirit was seen dancing and laughing, good fortune would come, but if domovoi extinguished candles, doom and misfortune would come to the house.

https://listverse.com/2016/04/05/10-weird-beings-from-slavic-mythology-and-folklore/

Rusalka-Slavic mythology

Rusalka

Rusalka is something akin to mermaids or sirens, but rusalka had legs and she could walking on the grounds. The ancient slavic were believed that this creatures were formed after terrible and awful death of a women.  Rusalki was beautiful young nymphes, who was living on the marsh or coastes. They used to love dancing in the moonlight and climbing on the trees. They were keeping out of the humans, but they were helping people by providing life-giving moisture. In the ancient times there was a special holiday to honor these beautiful creatures. It was called Rusalki week and on these ceremony people were dancing in the moonlight and were keeping out of water reservoirs. In the 19th century, the main goal of Rusalka turned into drawing young men in the watery depths and killing by tickling.

http://www.ancient-origins.net/myths-legends/rusalka-mythical-slavic-mermaid-006738