An alp is typically male, while the mara and mart appear to be more feminine versions of the same creature. Its victims are often females, whom it attacks during the night, controlling their dreams and creating horrible nightmares (hence the German word Alptraum["elf dream"], meaning a nightmare).
An alp attack is called an Alpdruck, or often Alpdrücke, which means "elf pressure". Alpdruck is when an alp sits astride a sleeper's chest and becomes heavier until the crushing weight awakens the terrified and breathless dreamer. The victim awakes unable to move under the alp's weight.
Sexual attacks by the alp are rare.
The alp is often associated with vampires because it will drink blood from the nipples of men and young children, though women are the preferred victim of the invariably male alp.
The alp is best known for its shapeshifting abilities, similar to the creatures from werewolf lore. It may change into a cat, pig, dog, snake or a small white butterfly. It has also been said that it can fly like a bird and ride a horse. The alp always wears a hat, giving it an almost comical appearance. The hat is known as a Tarnkapp (the literal translation being "camouflage cap" or "cap of concealment") which is simply a hat (or less commonly a veil) that gives the alp magic powers and the ability to turn invisible while worn.
The hat is visible no matter what shape the alp takes. An alp who has lost this hat will offer a great reward for its safe return. The alp also possesses an "evil eye" whose gaze will inflict illness and misfortune. Removing or damaging this eye also removes the alp's malicious intentions.
The Alps I have here are dangerous, rare and very malicious. These are custom conjures because some are very very dangerous and only fit with certain types of people. I have one here with me that is tricky, and very very adept at breaking the rules. I keep them for 4 months before I list them, I need to know the ins and outs of what they are and are not capable of. These are capable of being very dangerous and malicious. But in the right hands, they would make EXCELLENT companions.