Muma Pădurii literally means "the Mother of the Forest", though "mumă" is an archaic version of "mamă" (mother), which has a fairy-tale overtone for the Romanian reader (somewhat analogue to using the archaic pronouns like "thou" and "thy" in English). A few other such words, typically protagonists of folk-tales, have this effect.
Muma Pădurii is a spirit of the forest in a very ugly and old woman's body. Sometimes she has the ability to change her shape. She lives in a dark, dreadful, hidden little house.
She is thought to attack children, and because of this, a large variety of spells (descântece in Romanian) are used against her.
This (step-) mother of the forest kidnaps little children and enslaves them. In one of the popular stories, at some point, she tries to boil a little girl alive, in a soup. However the little girl's brother outsmarts Muma Pădurii and pushes the woman-monster in the oven instead, similar to the story of Hansel and Gretel. The story ends on a happy note when all kids are free to go back to their parents.