Comic Title: Superboy #99
Publisher: DC (National Periodical Publications, Inc.)
Address: 575 Lexington Avenue, New York, NY
Cover Date: September 1962
On Sale Date: July 3, 1962 Copyright Date July 3, 1962
Source: Library of Congress, Periodicals 1962

Frequency: Monthly, with the exception of Feb., May, Aug., and Nov.
Cover Price: $0.12
Page Count: 32
Editor: Mort Weisinger

Title: "The Doom That Destroyed Clark Kent"
Pages: 9

Feature(s):
Superboy (of Earth-1)

Artist: George Papp

Feature Character(s)

• Superboy (last appearance in Superboy #99; next appearance in Superboy #99)

Supporting Character(s)

• Jonathan Kent (last appearance in Adventure Comics #298; next appearance in Superboy #100)
• Martha Kent (last appearance in Superboy #99; next appearance in Superboy #100)
• Lana Lang (last appearance in Superboy #99; next appearance in Superboy #99)

Villain(s)

• A crystal creature (no further appearances)

Other Character(s)

• Dr. Hoskins and his assistant (no further appearances)
• Several Smallville citizens (no further appearances)

Synopsis:
Superboy drills a hole to the center of the Earth in order to super-heat a chemical compound for some scientists. A crystal creature emerges from the hole and works its way across the face of the Earth. Superboy attempts to destroy it, but the crystal rebuilds itself after being damaged. Finally, Superboy uses radioactive rocks to block the creature’s path and return it to the center of the Earth. Clark Kent, who was seen devoured by the creature, then emerges from an underground cavern, that he pretends he fell into; thus Superboy’s secret identity is saved.