The Dark Phantom Strikes! was a live, episodic radio mystery and supernatural-detective drama broadcast by WXXL Radio in 1926, just days into the station going on the air. The show, on which Gregor was sound engineer, was written by a team of writers. The program starred the Dark Phantom — a pulp vigilante armed with his "Tibetan Darkness Power" which could render him invisible — alongside his sidekick Buddy, who faced off against the machinations of Dark's Phantom's arch nemesis: criminal mastermind, Marco Phillips.