Attack of the Giant Leeches (1959)

Attack of the Giant Leeches is a low-budget 1959 science fiction film from American International Pictures, directed by Bernard L. Kowalski and produced by Gene Corman. The screenplay was written by Leo Gordon. It was one of a spate of monster movies produced during the 1950s in response to cold war fears; in the film, a character speculates that the leeches have been mutated to giant size by atomic radiation from nearby Cape Canaveral.

Plot
In the Florida Everglades, a pair of larger-than-human, intelligent Leech are living in an underwater cave. They begin dragging local people down to their cave where they hold them prisoner and slowly drain them of blood.
One of the first people to be so taken is the local vixen, Liz Walker, played by Yvette Vickers. After a couple of gratuitous displays of flesh (Vickers appeared as the centerfold in the July 1959 issue of Playboy), and some running around on her husband (Bruno VeSota), Liz finds herself a prisoner of the leeches along with her current paramour. Game warden Steve Benton (Ken Clark (actor)) sets out to investigate their disappearance. Aided by his girlfriend Nan Grayson (Jan Sheppard) and her father, Doc Grayson, he discovers the cavern.
The monsters are finally destroyed when Steve, Doc, and some state troopers blow up the cavern with dynamite.
Cast
Ken Clark (actor) as Steve Benton
Yvette Vickers as Liz Walker
Jan Shepard as Nan Greyson
Michael Emmet as Cal Moulton
Tyler McVey as Doc Greyson
Bruno VeSota as Dave Walker
Gene Roth as Sheriff Kovis
Dan White (actor) as Porky Reed
George Cisar (actor) as Lem Sawyer
Guy Buccola as Giant Leech
Joseph Hamilton as Old Sam Peters
Walter Kelley as Mike
Ross Sturlin as Giant Leech

From publicdomainmovies.net