Doppelgänger is a term used in the occult and supernatural to describe the phenomenon of encountering a ghostly duplicate of oneself. It is believed to be a manifestation of a person's other self, their double, and is often seen as a harbinger of bad luck or an ominous sign of impending doom.
In traditional folklore and superstition, encountering one's doppelgänger was thought to be a sign of impending death or serious illness. In some cultures, it was believed that seeing your doppelgänger meant that your soul was in peril and that you needed to take immediate action to protect it.