| Unofficial Challengers of the Unknown Index |
Credits:
| Story | Arnold Drake |
| Art | Bob Brown |
| Lettering | Stan Starkman |
| Editing | Murray Boltinoff |
Feature Character(s):
- Challengers of the Unknown:
- Ace Morgan (last in flashback in Challengers of the Unknown Vol. 3 #16)
- Rocky Davis (last in flashback in Challengers of the Unknown Vol. 3 #16)
- Red Ryan (last in flashback in Challengers of the Unknown Vol. 3 #16)
- Prof Haley (last in flashback in Challengers of the Unknown Vol. 3 #16)
Villain(s):
- Two artificial Volcano Men (both last in issue #27/2; join to form one large Volcano Man; destroyed)
Location(s):
- Challengers Mountain
- Malina Island
Story Reprinted in:
- Brave and the Bold #98/2 (October-November 1971)
- Showcase Presents Challengers of the Unknown #2 (2008)
Credits:
| Art | Bob Brown |
| Lettering | Stan Starkman |
| Editing | Murray Boltinoff |
Feature Character(s):
Supporting Character(s):
- Cosmo (revealed to be J'Suna, D'Jann's pet; last appearance)
Villain(s):
- Mastermind (first appearance; a criminal mastermind; uses D'Jann's Substance Converter gun to attack the Challengers)
Other Character(s):
- D'Jann (first appearance; an alien)
Comment(s):
- Even though Cosmo remains on Earth with the Challengers, he makes no further appearances.
Story Reprinted in:
- Showcase Presents Challengers of the Unknown #2 (2008)