| Issue | #8 |
| Published | June-July 1959 |
| Cover Price | 0.10 USD |
| Pages | 36 |
| Editing | Jack Schiff |
| Characters | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis]; Juhl |
| Genre | Adventure |
| Pencils | Jack Kirby |
| Inks | Wally Wood |
| Reprinted | in Challengers of the Unknown Archives (DC, 2003 series) #2 (May 2004); in Showcase Presents Challengers of the Unknown (DC, 2006 series) #1 |
| Characters | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis]; June Robbins; Marie; Drabny |
| Synopsis | June's friend Marie comes to meet the Challengers to ask them to investigate weird events in her home country of Mordania. There they meet and fight the evil Drabny, whose scientific inventions have enabled him to take over Mordania. |
| Genre | Adventure |
| Script | Dave Wood; Jack Kirby |
| Pencils | Jack Kirby |
| Inks | Wally Wood |
| Notes | Introduction of Drabny, later a member of the Challenger Haters. |
| Reprinted | in Super DC Giant (DC, 1970 series) #S-25 (July-August 1971); in Challengers of the Unknown (DC, 2003 series) #2 (May 2004); in Showcase Presents Challengers of the Unknown (DC, 2006 series) #1 |
| Characters | Challengers of the Unknown [Ace Morgan; Professor Haley; Red Ryan; Rocky Davis]; Juhl; Kra |
| Genre | Adventure |
| Script | Jack Kirby ? |
| Pencils | Jack Kirby |
| Inks | Wally Wood |
| Notes | Introduction of Kra, later a member of the Challenger Haters. |
| Reprinted | in Challengers of the Unknown Archives (DC, 2003 series) #2 (May 2004); in Showcase Presents Challengers of the Unknown (DC, 2006 series) #1 |