troll

In Scandinavian folklore, a giant supernatural being (sometimes the size of a dwarf) with evil powers in the dark. Trolls live in caves or castles in the mountains and cannot survive in sunlight. They are described as living in families, sometimes tribes, and often as having a king.

Today they have become mere bogies in children's books. In English stories many of the giants (as in ‘Jack and the Beanstalk’) and gnomes are descendants of trolls in Scandinavian folklore, and pixies and malicious fairies are close relations.