An alp is a creature that enjoys tormenting dreams and sitting on the chest of its victims, leaving them to awake in a panic and out of breath.
Often mistakenly categorized as a "vampire" due to its habit of drinking blood from nipples (as a treat, not something that they feed on like a vampire) the alp is really more similar to a dark elf or dwarf, though many sources also may liken it to a ghost or demon as well. Whatever the case, the alp is a creature of nightmares! In their descriptions, alps can range anywhere to an impish white dwarf or elf, to a hairy little man, or any variety of animal no bigger than a horse. No matter what the appearance, the alp is described to wear a hat or head covering of some sort. This is their Tarnkappe, the source of the alp's powers.
Alps enjoy "pressing" or "riding", which involves sitting astride a sleeper's chest as one would a horse and making himself progressively heavier until the crushing weight awakens the victim.
Alps prefer to victimize the wicked, but may choose a victim for any percieved slight as is the capricious nature of elf and fairy kind.
An alp can be disuaded from continuing its nightly visits through catching him in the act, trapping him in the room and demanding it (it will take a lot of convincing since he will insist), getting another person to stay up and capture him, or shoving lemons in his mouth.