Volcanic activity frees giant scorpions from the earth who wreak havoc in the rural countryside and eventually threaten Mexico City.
Richard Denning
Hank Scott
Mara Corday
Teresa Alvarez
Carlos Rivas
Artur Ramos
Mario Navarro
Juanito
Carlos Múzquiz
Dr. Velazco
Pascual García Peña
José de la Cruz
Fanny Schiller
Florentina
Arturo Martínez
Major Cosio
Pedro Galván
Father Delgado
José Chávez
Train conductor (uncredited)
Manuel Sánchez Navarro
Victor Steven (uncredited)
Roberto Contreras
Chumacho (uncredited)
Quintín Bulnes
Lineman killed on pole (uncredited)
Isabel Vázquez
Villager (uncredited)
Leonor Gómez
Bob Johnson
Narrator (voice) (uncredited)
Paul Yawitz
Story
David Duncan
Screenplay
Robert Blees
Edward Ludwig
Director
Willis H. O'Brien
Visual Effects
Pete Peterson
Animation
Frank Melford
Producer
Wah Chang
Creature Design
Jack Dietz
Special Effects Supervisor
Lionel Lindon
Director of Photography
Edward Fitzgerald
Art Direction
Paul Sawtell
Original Music Composer
