Academic researchers are chased by a nuclear-hot specimen of ancient Mayan blob.
| Actor | Role |
|---|---|
 John MerivaleDr. John Fielding | Dr. John Fielding |
 Didi SullivanEllen Fielding | Ellen Fielding |
 Gérard HerterMax Gunther | Max Gunther |
 Daniela RoccaLinda | Linda |
 Vittorio AndréProf. Rodriguez | Prof. Rodriguez |
 Daniele VargasBob | Bob |
 Nerio BernardiPolice Inspector | Police Inspector |
 Giacomo Rossi StuartProf. Rodriguez's Assistant | Prof. Rodriguez's Assistant |
 Gail PearlIndian Dancer | Indian Dancer |
 Tom FelleghyAstronomo | Astronomo |
 Arturo DominiciNieto | Nieto |
 Mario BavaMexican at police station (uncredited) | Mexican at police station (uncredited) |
 Renzo PalmerNarrator (voice) | Narrator (voice) |
 Leslie DanielsProf. John Fielding (voice) | Prof. John Fielding (voice) |
 Renato De CarmineProf. John Fielding (voice) | Prof. John Fielding (voice) |
 Stefano SibaldiMax Gunther (voice) | Max Gunther (voice) |
| MMichele MalaspinaProf. Rodriguez (voice) | Prof. Rodriguez (voice) |
| RRolf TasnaBob (voice) | Bob (voice) |