D is for Doppelgänger

Today's belated trip sponsored by the letter D takes us throughout Europe with a brief dip into Egypt, since while the word is German, there are several mythologies which have their own versions of it.

Name: Doppelgänger (means "double walker")

Type: Paranormal, usually ghostly double.

Origin: European mythology/folklore

Description: They are typically described as the feeling of glimpsing at oneself in your peripheral vision, somewhere you couldn't possibly be catching your reflection. They can be either shadowy, vague figures or life-like.

Interesting Facts: The mythologies I found that include doppelgängers are Norse mythology, in which it's a spirit predecessor who goes before the living person and can be seen performing their actions before they do. It is called a vardøger. Finnish mythology has an etiäinen (which means "a firstcomer") that is a spirit summoned by a shaman or person in great need so they can receive information. It looks and acts like the person who summoned it in order to obtain the message.

Finally, there's the ka (meaning "spirit double") in Ancient Egyptian mythology, which is a copy of the original person's feelings and memories. It's used in the Egyptian's take on the Trojan War in "The Greek Princess" where Helen's ka misled Paris of Troy to help stop the war.

Something else of interest is the fact that according to Nature, a scientific magazine, while being treated for epilepsy by using electromagnetic stimulation of the patient's brain, the woman experienced the awareness of a doppelgänger near her, even though she was psychologically healthy. Also, several famous people such as Johann Wolfgang von Goethe and Abraham Lincoln reportedly experienced their ghostly doubles as well.

Source: Wikipedia. 

Have you heard of the doppelgänger before? If so, where did you learn about it?