Hiisi (Finnish pronunciation: [ˈhiːsi]; plural hiidet [ˈhiːdet]) is a term in Finnic mythologies, originally denoting sacred localities and later on various types of mythological entities.
In later, Christian-influenced folklore, they are depicted as demonic or trickster-like entities, often the autochthonous, pagan inhabitants of the land, similar in this respect to mythological giants. They are found near salient promontories, ominous crevasses, large boulders, potholes, woods, hills, and other outstanding geographical features or rough terrain.