Bumpy (1981)

A brother and sister called Kusti and Iti get lost in a forest while picking strawberries and are captured by an evil forest hag, who uses the two kids as slave labor - Kusti is put to work around the farm, while Iti looks after the hag's mischievous son, whom she names Bumpy due to the horn-like bumps on his head. When a chance to escape arises, the two kids take Bumpy with them. But how will a wild forest rascal like Bumpy adjust to life with Iti and Kusti's family?