The weight on your chest

Sometimes you wake while your body is still in the muscle stillness of REM sleep. You cannot move for a few seconds, and the dreaming brain may add a presence in the room or pressure on the chest. Cultures across the world named it: the old hag in Newfoundland, kanashibari in Japan. It is frightening but harmless, and it passes. Slow breathing and small movements of a finger help it end sooner.