Even when the door is closed, Alps can enter a bedroom. They slip in through keyholes or tiny cracks in the wall. Once they’re inside, they can only leave through the same hole they entered. Plugging up the holes is not advised or the alp will stay around forever.
Alps enter dreams by transforming into a mist and seeping into the sleeping person. Sometime they transform into a snake and slither in through the nostrils and mouth. Working from inside inside the person, the alp creates horrible dreams. The German word for nightmare, Alpdrucke, means ‘alp pressure.’
Like elves, alps play other dirty tricks while people are sleeping. They often ride horses all night and bring them back in the morning exhausted. They tangle people’s hair by sucking on it and they put dirty diapers back on babies.
Supposedly, people whose eyebrows join in the middle of their forehead have the power to send alps to plague their enemies. Getting rid of an alp can be tricky. Alps are incredibly persistent and will travel great distances to torture their victims. A horse head supposedly repels them. This may be a case, however, of the cure being worse than the affliction. Sleepers who feel the alp pressure on their chest can call out “come tomorrow and drink with me.” This should force the alp to leave and compel the uni-browed person who sent him to visit the next day.