The script was evidently passed along out of inventory from King, like Gary Poole's in the same issue and Dick Wood's in the next few. The writer is Pat Fortunato, who wrote the earlier Girl Phantom story, "The Riddle of the Witch," in #24. Note the profusion of exclamation points and question marks in one panel; this would be a noticeable characteristic of Fortunato's work in her credited (and uncredited) work on UFO Flying Saucersat Gold Key.
This post was just going to ID that one Charlton story, but upon seeing how other issues have been attributed on the Grand Comics Database, I ended expanding it by a lot. On the Gold Key issues, the GCD notes that some 40 years after these were published, Bill Harris said he wrote all the Phantom stories. The Comic Reader 40 is cited for attributing the story in #11 as by "Dick Wood?" in addition to "Bill Harris?" That story's note does suggest that actually Harris said he wrote the adaptations of Lee Falk strip stories, which makes more sense. TCR32 also mentions Wood: "Dick Wood is still scripting SOLAR, and he'll be handling the original PHANTOM scripts." The source of the contemporary Gold Key news at TCR? Gold Key editor Bill Harris.
For your perusal: panels from the Claw story in Daredevil Comics 22 (Feb/46, Lev Gleason), "Interplanetary Olympics" in Jigsaw2 (Dec/66, Harvey), and "The Terror Tiger" in Phantom21, all with the use of "Kazar" for "Huzzah"--like "Great suffering Hannah" elsewhere, a sign of Dick Wood's scripting.
I suppose most of the stories not listed here through #30 are indeed by Bill Harris.
Some Phantomwriters
Gold Key/King/Charlton
in Mandrake the Magician
King
Some Phantomwriters
Gold Key/King/Charlton
Apr/65 | 11 | Blind Man's Bluff | Dick Wood |
June/ | 12 | The Beast of Bengali | Wood |
Aug/ | 13 | The Phantom Chronicles | Wood |
Nov/66 | 19 | The Astronaut and the Pirates | Wood |
The Masked Emissary | Wood | ||
Jan/67 | 20 | The Adventures of the Girl Phantom | Wood |
The Invisible Demon | Jerry Siegel | ||
Mar/ | 21 | The Terror Tiger | Wood |
Mar/ | 22 | The Secret of Magic Mountain | Wood |
Mar/ | 23 | Delilah | Wood |
Aug/ | 24 | The Riddle of the Witch | Pat Fortunato |
Oct/ | 26 | The Pearl Raiders | Wood |
Nov/ | 27 | The Story of Hero | Gary Poole |
Dec/ | 28 | Diana's Deadly Tour | Wood |
Feb/69 | 30 | The Secret of the Golden Ransom | Fortunato |
p: José Delbo i: Sal Trapani |
in Mandrake the Magician
King
Nov/66 | 2 | The Pirate Raiders | Wood |
Mar/67 | 4 | The Girl Phantom | Wood |