Academic researchers are chased by a nuclear-hot specimen of ancient Mayan blob.
John Merivale
Dr. John Fielding
Didi Sullivan
Ellen Fielding
Gérard Herter
Max Gunther
Daniela Rocca
Linda
Vittorio André
Prof. Rodriguez
Daniele Vargas
Bob
Nerio Bernardi
Police Inspector
Giacomo Rossi Stuart
Prof. Rodriguez's Assistant
Gail Pearl
Indian Dancer
Tom Felleghy
Astronomo
Arturo Dominici
Nieto
Mario Bava
Mexican at police station (uncredited)
Renzo Palmer
Narrator (voice)
Leslie Daniels
Prof. John Fielding (voice)
Renato De Carmine
Stefano Sibaldi
Max Gunther (voice)
Michele Malaspina
Prof. Rodriguez (voice)
Rolf Tasna
Bob (voice)