Alter Ego has multiple meanings:

• Alter Ego is a game for the Commodore 64 computer.
• An alter ego (from Latin, "other I") is another self, a second personality or persona within a person. The term is commonly used in literature analysis and comparison to describe characters who are psychologically identical.
• Alter Ego is a brand of Wizards of the Coast.
• Alter Ego is a Industrial-Rave techno group.

The term and concept are also frequently used in popular fiction, like comic books, for the secret identity of a superhero, vigilante or crimefighter:

• Superman's alter ego is Clark Kent,
• Batman's is Bruce Wayne,
• Spider-Man's is Peter Parker
• Doctor Octopus's is Otto Octavius
• The Hulk's is Bruce Banner
• Dr. Jekyll's is Mr. Hyde in The Strange Case of Dr. Jekyll and Mr. Hyde by Robert Louis Stevenson