Un equipo de documentalistas se traslada a la selva amazónica para localizar a la tribu indígena de los Shirishama. Al equipo se une como guía un misterioso ex sacerdote que se dedica a la caza y asegura saber dónde se encuentran los Shirishama. Pero, en realidad, lo que hace es guiarlos a la caza de un reptil único en el mundo: una inmensa serpiente anaconda de doce metros de largo.
Un laboratorio científico mantiene en cautividad a una anaconda gigante con fines experimentales. Cuando ésta y otra de las serpientes del laboratorio escapan y empiezan a atacar a los científicos, un equipo de especialistas deberá intervenir para dar caza a los animales.
Una cría de anaconda, genéticamente mejorada, se ha regenerado y crece monstruosamente. La cría sedienta de sangre es aparentemente invencible, y se desliza entre explosiones y disparos para regenerarse y alimentarse insaciablemente de todo lo que se encuentre en su camino.
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.
Una mujer intenta conseguir pruebas contra una empresa biológica que es responsable por la muerte de su prometido. Junto a un amigo parte hacia una isla donde varias muertes se dan frecuentemente.
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.
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.
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.
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.
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.
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.