An Alp (plural Alpe or Alpen) is a supernatural being in German folklore. Not to be confused with the similarly named Alp-luachra, the Alp is sometimes likened to a vampire, but its behavior is more akin to that of the incubus. It is distinct from both of these creatures in that it wears a magic hat called a Tarnkappe, from which it draws its powers. The word Alp is the German form of the word that comes into English as elf, both descended from Common Germanic. It is also known by the following names: trud, mar, mart, mahr, schrat, and walrider. Many variations of the creature exist in surrounding European areas, such as the Drude or, in the British Isles, the Old Hag, related to now commonly recognized sleep paralysis.