Because of their unknowable natures, many attribute small accidental happenings with a spook.
For this, they occupy a place in folks' minds similar to the Invisible Snark, though spooks are known to truly occupy the Auld. (This doesn't stop many people from claiming I.S. to be 'The King of the Spooks.)
They are commonly thought to be the spirits of commonfolk who weren't ready to ascend into the 50th dead world. There continued state of existence, however, is rarely seen as threatening and is most feared by that of children, who may have a hightened sense of their presence or may even be able to see them occasionally.
One more common power attributed to spooks is the revival of small animal life, something such as brining a baby bird back from the dead or a tufties from a nasty fall from a prank.