Them!

“A horror horde of crawl-and-crush giants clawing out of the earth from mile-deep catacombs!”

Sgt. Ben Peterson (James Whitmore) is a state police officer who finds signs of a giant mutant ant in the American desert southwest, far bigger than anything natural. Gordon Douglas shoots it in black and white as the case grows to take in an FBI agent, Robert Graham (James Arness), and the Army. Ben ends up beside Dr. Harold Medford (Edmund Gwenn) and his daughter Pat (Joan Weldon), the two entomologists who know exactly what he has found.