Comic Title: Challengers of the Unknown #21
Publisher: DC (National Comics Publications, Inc.)
Address: 575 Lexington Avenue, New York, NY
Cover Date: Aug/Sep 1961
On Sale Date: June 13, 1961 Copyright Date June 13, 1961
Source: Library of Congress, Periodicals 1961

Frequency: Bi-monthly
Cover Price: $0.10
Page Count: 32
Editor: Jack Schiff

Title: "The Weird World That Didn't Exist"
Pages: 12

Feature(s):
Challengers of the Unknown (of Earth-1)

Artist: Bob Brown

Reprinted In:
Showcase Presents:Challengers of the Unknown Vol. 2 TPB (2008)

Feature Character(s)

• Challengers of the Unknown (last appearance in Challengers of the Unknown #20; next appearance in Challengers of the Unknown #21)
• Ace Morgan (last appearance in Challengers of the Unknown #20; next appearance in Challengers of the Unknown #21)
• Rocky Davis (last appearance in Challengers of the Unknown #20; next appearance in Challengers of the Unknown #21)
• Red Ryan (last appearance in Challengers of the Unknown #20; next appearance in Challengers of the Unknown #21)
• Prof. Haley (last appearance in Challengers of the Unknown #20; next appearance in Challengers of the Unknown #21)

Supporting Character(s)

• June Robbins (last appearance in Challengers of the Unknown #20; next appearance in Challengers of the Unknown #21)

Villain(s)

• A criminal gang (no further appearances)

Other Character(s)

• Albert D. Farnum and a movie crew (no further appearances)

Synopsis:
The Challs are called to help June at a remote location. When they arrive, they are knocked unconscious and transported to what appears to be an alien world. After rescuing a girl, they encounter several alien beings, but Ace realizes they are phonies. June reveals herself as the alien girl and explains that they were being used to film a movie.

Suddenly, the Challs and the movie crew are attacked by criminals using the props from the movie. Rocky and Red are captured and taken to the movie city set. One of the actors helps them escape, and with the help of Ace and Prof who have commandeered some movie machines of their own, the Challs defeat the crooks. The action is all caught on film, allowing the movie to be made.