The Monster That Challenged the World

The Monster That Challenged the World aka The Jagged Edge and The Kraken is a 1957 sciencefiction monster movie, about an army of giant mollusks that emerge from Californias Salton Sea. Directed by Arnold Laven, the film starred Tim Holt and Audrey Dalton.

A young couple disappear after swimming. U.S. Navy divers investigate and discover a giant egg and the body of one of the victims. The divers are attacked by a giant mollusk, which kills one of the divers. The mollusk attacks the boat but Twill stabs it in the eye with a grappling hook. The egg is taken to the U.S. Navy lab for study and kept under temperature control to prevent it from hatching.The mollusks escape into the irrigation canal system, attacking livestock, a lock keeper, a trysting couple and others. Navy divers locate the group of mollusks in the canal system, and use explosives to destroy them. ........

Source: Wikipedia