Una troupe cinematografica parte su una chiatta fluviale per realizzare un documentario all'interno della foresta brasiliana. Ne fanno parte l'antropologo Steve Cale, la regista Terri, l'operatore alla macchina Danny, il tecnico del suono Gary, la produttrice Denise e l'attore Warren. L'obiettivo è la ricerca del leggendario popolo degli Indios Shirishama, e a guidare l'imbarcazione c'è il locale Mateo. Il viaggio comincia e, dopo qualche tempo, il gruppo incontra un uomo, Paul, bloccato a bordo di una barca senza equipaggio. Viene fatto salire e, informato dello scopo del viaggio, si offre di fare da guida, dicendosi molto esperto dei luoghi. In realtà Paul ha un motivo personale per ridiscendere il fiume: trovare un letale anaconda assassino lungo dodici metri, un predatore talmente mortale da essere diventato a sua volta leggendario.
Uno degli anaconda della nuova stirpe geneticamente modificata si è rigenerato per dare vita a un nuovo terrificante capitolo della saga! Un magnate moribondo assume un dottore per estrarre il siero della vita eterna da alcuni fiori rarissimi detti "orchidee maledette". Ma prima di iniettare la miracolosa medicina al paziente, il medico ne sperimenta gli effetti su un serpente appena nato. Nel giro di una notte il piccolo rettile si trasforma in un animale dalle dimensioni mostruose, dotato di un appetito insaziabile, che lo porta a divorare tutto quello che incontra sulla sua strada.
After his fiancé sudden death, Qin Yu is convinced Cass Corporation is somehow involved and is determined to find the truth. Booking passage on the same cruise ship as former Cass employee, Jason, Qin Yu follows him. Qin Yu hopes to secure the information he needs on Cass to be able to testify against them in court. But Qin Yu isn’t the only person on board hoping to gain intel on Cass. Desperate for a story, reporter Feng Li tails both Qin Yu and Jason, booking passage on the same cruise. Unfortunately, no one has much of a chance to gain information as the ship is suddenly attacked by giant mutant snakes. Escaping the attack, the survivors find themselves on the very island Cass Corporation has been conducting their illegal experiments. Hunted by monsters of all sorts, will any of the survivors find a way to bring Cass down and make it off the island alive?
Due giganteschi serpenti sfuggono al controllo dei ricercatori che li hanno allevati in un laboratorio segreto e si dirigono verso i centri abitati. Bisognerà fermare i pericolosi rettili - sui quali erano in corso importanti studi scientifici - prima che si riproducano.
A hybrid creature - half piranha and half anaconda -- attacks a low-budget horror movie crew on location near her nest when her egg is stolen. Now they must outrun and kill the deadly piranhaconda as well as stop the mad scientist who stole the egg - before they all become dinner.
A set of vipers has been taken by scientists to mutate them to make a cure for cancer. As their experiment goes awry, the vipers escape into the woods - they're not only biting people, they're actually killing people, in a little town.
A gigantic serpent is captured on a remote island and shipped to an American college for experimentation.
During the construction of luxury apartment buildings a huge nest of thousands of snakes is discovered. Francis Chang (the boss) refuses to delay the construction and orders to kill all the animals. He is repeated warned by his wife, who had some nightmares concerning him and the snakes. They do not manage to kill all snakes and so they take revenge on the construction workers and Francis Chang. Soon thousands of killer snakes under the lead of a giant Boa invades the building an kill all the new inhabitants. Even a snake master can't stop them.
In an old house, a man is bitten to death by a snake. The special services and the media congregate but are only able to find a few snakes. Later, a group of cobras invade the building which threatens the lives of the habitants.
An American submarine leaves Tierra Del Fuego, and one of its crew has secretly brought aboard a container full of poisonous snakes which escape storage and bite key personnel on the submarine, causing an accident that cripples the vehicle so that it drops to the bottom of the Southern Ocean. Worse still, the snakes are still at large on the submarine and complicate the efforts of the crew to escape the sunken vessel.
A woman transforms into a snake-headed killer.
The King of the Snake Monsters is attempting to revert back to human form but is opposed by the womanizing owner of a popular restaurant that specializes in medicinal snake soup.
Police investigate a strange series of snakebite deaths.
A married man falls in love with a beautiful tour guide but is unaware of her symbiotic relationship with a deadly cobra that has killed all of her previous suitors. This was remade at least two other times.