Wikipedia posted:

An alp is a nightmare creature originating from Teutonic or German folklore.

Not to be mistaken with the similarly named Alp Luachra, the alp is sometimes likened to a vampire, but its behavior is more like that of the incubus. The word "alp" is also a variation on the word "elf", and it also is known by the following names: trud, mare, mart, mahr, Schrat, and Walrider. Many other variations exist in surrounding European areas.

An alp is typically male, while mara and mart appear to be more feminine versions of the same creature. Its victims are often female, and it usually attacks during the nighttime, controlling dreams and creating horrible nightmares. An alp attack is referred to as an alpdrücken, as "pressing" is a favorite night torment of the alp. The alp "sits upon" a sleeper's chest and becomes heavier until the crushing weight awakens the terrified (and breathless) dreamer. They may awake terrified and unable to move under the alp's weight. This may have been an early explanation for sleep apnea and sleep paralysis, as well as night terrors. It may also include lucid dreams. An alp will repeat these sessions until it is repelled sufficiently, for it is quite persistent and determined once it selects its victim, and have been known to travel great distances to and from their favorite haunt.

The reason it is sometimes associated with vampires is because it may drink the blood from the nipples of men and young children. Alps also exhibit an elf-like tendency for mischief, like souring milk and re-diapering a baby. A maid must sign a cross on the diaper or the alp will put the soiled diaper back on it. They also enjoy tangling hair into "elfknots" or chewing and twisting horse's tails. They will ride a horse to exhaustion during the night and may sometimes crush small farm animals to death during a pressing attack.

It is said that alps originated from rather friendly elf-like beings, then turned toward more negative and malevolent ways.[citation needed] The alp, in many cases, is considered a demon, but there have been some instances in which the alp is created from the spirits of recently dead relations. Children may become an alp if a mother needs to use a horse collar to ease the pain during an extremely long and torturous childbirth. Also, a child born with a caul or stillborn may become an alp. As with the case of werewolves, sometimes a human or animal may become an alp during the night. Proof of this is injuring or marking the alp during the attack and seeing the being with a similar mark during the day. Also, people who have eyebrows that meet are suspected to be alps.

Sometimes an alp is a spirit sent by a witch or a person wishing harm on another. Tricking an alp shall lead you to the sender.

The alp also is known for its shape-shifting 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. In almost all accounts and manifestations, the Alp is said to wear a hat, giving it an almost comical appearance. The hat is said to be a cloak of invisibility (Tarnkappe), essentially a cloak with a hood or—in the case of the alp—simply a hat that possess magic powers and gives the alp the ability to turn invisible. An alp who has lost this hat will offer a great reward for its safe return.

Protections against an alp include laying a broomstick under a pillow, iron horseshoes hung from the bedpost, placing shoes against the bed or placing a mirror on the chest. Steel and crosses are also used. If awoken by the alp and finding him still there, one can address him by asking him to return in the morning to borrow something or have coffee. It is said it will dash away at once, arriving in the morning in his "true" form for his gifts. Also, plugging up any holes, specifically keyholes, before a visitation will keep the demon out, while plugging them during a visitation will invariably seal him in the room, as they often leave only through their original entrance. A light kept constantly on during the night will also effectively ward off an alp, as they tend to shrink from the light.