A brilliant surgeon encases his dead son's brain in a large robot body, with unintended results...
| Actor | Role |
|---|---|
 John BaragreyDr. Henry Spensser | Dr. Henry Spensser |
 Mala PowersAnne Spensser | Anne Spensser |
 Otto KrugerDr. William Spensser | Dr. William Spensser |
 Robert HuttonDr. John Robert Carrington | Dr. John Robert Carrington |
 Ross MartinDr. Jeremy 'Jerry' Spensser | Dr. Jeremy 'Jerry' Spensser |
| EEd WolffThe Colossus | The Colossus |
 Charles HerbertBilly Spensser | Billy Spensser |
| DDick NelsonCharles - Chauffeur-Butler | Charles - Chauffeur-Butler |
| RRoy EngelPolice Inspector | Police Inspector |
 Charles SherlockAirline Pilot | Airline Pilot |
 George DouglasNot listed | Not listed |
| SSam HarrisNot listed | Not listed |
| LLarry KerrNot listed | Not listed |
 Harold MillerNot listed | Not listed |
| FFoster H. PhinneyNot listed | Not listed |
| MMax PowerNot listed | Not listed |
 Jack RichardsonNot listed | Not listed |
| CCourt ShepardNot listed | Not listed |
| BBert StevensNot listed | Not listed |
| EEd WolffNot listed | Not listed |