The word stems from German and means "Body double". The word has its importance in spiritual circles, where it was believed that a person in great distress can make a hologram  - even thousands of miles away. It can be a call for help, or just to connect with the family in the person's last breath in an accident.

Spiritists are actively working with this dobbelgaenger, for example during seances.

A dobbelgaenger can appear as a mist, shadow, incomplete entity or as a full-body entity, and it is reported that people are able to communicate with them.
 
Watercolor painting, showing couple meeting their Dobbeltgänger

Dante Rossetti: "How They Met Themselves"  - a presentiment of Death (1840)