When Earth was invaded by the Crime Syndicate from Earth 3, Lex Luthor activated his secret project: a clone of Superman. The cloning process required 10 years but due to the Syndicate’s invasion, Luthor was forced to use Subject B-0 prematurely. The 5 years shaved from the process rendered B-0, or Bizarro, unable to speak and saddled with limited intelligence while possessing majority of Superman’s powers.
From – Forever Evil #2
