Kolchak: The Night Stalker ( TV Series 1974 1975) S01 E20 The Sentry

The government is keen to hush up a series of mysterious deaths at the Merrymount Institute, an underground archival facility. When Carl investigates, he determines that the victims were ripped apart as if attacked by a crocodile or other large lizard. He eventually discovers that the workers excavated a series of strange egglike objects, and that the eggs mother, a large prehistoric lizard, is attempting to retrieve them. Fleeing for his life, Carl must return the eggs to the mother and fend her off.