A poacher is out in the swamps late one night when he is faced with a ghastly monstrosity, resembling some shapeless, giant octopus. He fires a few shots at it and makes good his escape, but when he gets back to the local bar, he can't convince the regulars that he really has seen something out there. Meanwhile, the bar owner Dave (Bruno VeSota) is losing any control over his wife Liz (Yvette Vickers), a sultry siren who is growing dissatisfied with her marriage, and has her eyes on the opportunistic Cal (Michael Emmet). But the threat of the giant leeches will soon spell doom for them all...
Written by Leo Gordon, the Roger Corman production Attack of the Giant Leeches begins like a cross between The Postman Always Rings Twice and The Creature from the Black Lagoon, with its film noir love triangle relationship accompanied by rubber-suited actors playing the monsters, swimming out in the swamps. The whole atmosphere is stifling, from the oppressive danger of being eaten by the leeches to the smothering obsession Dave has with keeping his wife faithful to him - which he naturally fails to do. You can almost feel the sticky humidity in the air.
But what's this? Yes, there has to be a hero, and in this one it's Steve (Ken Clark) who, in contrast to most of the other characters, is a fine, upstanding game warden of the community. Steve gets suspicious when a blood-drained victim stumbles out of the undergrowth one night, and makes up his mind to track down the creatures responsible, despite receiving no help from the sceptical police. Unlucky for him that the leeches are keeping themselves well hidden, only emerging from the murky waters to drag another casualty to their lair.
The best reason to watch this is Vickers, who makes a strong impression as the slinky, petulant wife. The most effective scenes are the ones featuring her, whether bitchily scolding her hapless husband, or, in a surprisingly adult bit, canoodling with Cal - there's no doubt as to what they've been up to behind Dave's back. The film's best known highlight sees the furious Dave find the two lovers by the shore, and, holding them at gunpoint, he forces them into the swamp, only for them to be captured, screaming, by the monsters rising out of the depths.
Unfortunately the only sequence that comes close to the power of that one is where we see the leeches dining on their prisoners, attaching huge, sucker mouths to their necks and draining their blood through the wound. Now that Liz is out of action, we have to concentrate on the exploits of the cardboard Steve as he works out, in true B-movie fashion, what is killing people and how to stop it. The monster costumes are ambitious but none too convincing, and only half of the cast are worth watching, but Attack of the Giant Leeches has the advantage of a strong, creepy location and a solid first half that keeps you watching the more conventional second. Maybe not quite as good as its reputation, but it's enjoyable enough within the limits of its tiny budget. Music by Alexander Laszlo.