doppleganger

Noun

doppelganger (plural doppelgangers)

1. A ghostly double of a living person, especially one that haunts such a person.
   • "An orderly let out the news that you are here," she said. "But don't worry. We've sent out a doppelganger to fool the Sons, and the orderly has been sentenced to slavery under the pyramid builder for twenty lifetimes. I hate my brother! How dare he fight us with the sky falling?"1963, Lester del Rey, The Sky Is Falling

   Synonyms:

   double, doubleganger

2. An evil twin.
   • I've got a pervert doppelganger / He came from over the sea / He hangs around doing sexual crimes / And the blame is getting pinned on me1997, Momus, “My Pervert Doppelganger”, in Ping Pong

   Synonyms:

   alter ego

3. A remarkably similar double.
   • Stars in Their Eyes ran for 16 years from 1990, and had the "wow" factor moment of transforming a pub singer into their idol, as the contestant said the famous words: "Tonight Matthew, I'm going to be…" and then stepped out from a puff of dry ice as their musical doppelganger.2021 September 15, Laura Martin, “How talent shows became TV's most bizarre programmes”, in BBC

   Synonyms:

   lookalike, alter ego

4. A monster that takes the forms of people, usually after killing them.