A notion particularly found in H P Lovecraft-derived Horror, but frequently present in Fantasy. The forces of Evil often include chthonic beings who can be awoken by accident – the classic high-fantasy examples are the Watcher in the Lake and the Balrog in J R R Tolkien's The Lord of the Rings (1954-1955), who are awoken partly by meddling adventurers in Moria and partly by a general rising tide of evil. Rarely, Dark Lords may be awoken by meddlers, as with the Dominator in Glen Cook's The White Rose (1985).
Supernatural forces fought by Occult Detectives like William Hope Hodgson's Carnacki have often lain asleep until awoken by those prying into That Which Humanity Is Not Meant To Know. In Lovecraft, what is awoken usually has something to do with the Cthulhu Mythos gods or with the lost races who worshipped or fought them; the awakening is accordingly a double threat, since the changes invoked in the awakeners' Perception of humanity's place in the Universe may well cause madness.
A good sf example of an MS is the Blight in Vernor Vinge's (1944- ) A Fire Upon the Deep (1992; > SFE). [RK]
- The Encyclopedia of Science Fiction: Vernor Vinge.