A very bad or frightening dream.
Any bad, miserable, difficult or terrifying situation or experience that arouses anxiety, terror, agony or great displeasure.
A feeling of extreme anxiety or suffocation experienced during sleep; Sleep paralysis.
To have a nightmare.
A delusionary or otherwise unachievable goal that one feels compelled to pursue.
A flickering light or lantern, especially over bogs, swamps or marshes, held by a supernatural creature who uses it to lure travelers at night to their demise.