Anaconda is a film that is replete with stupidity and incongruity. It is one of the worst films in terms of how idiotic people can be when confronted with danger. The effects are really good and the pacing is tight. All that makes it a really good B-movie.
The plot involves Terri Flores (Jennifer Lopez) and her team of explorers seeking to document a native tribe somewhere along the Amazon river. They run into Paul Sarone (Jon Voight), a hunter who has great knowledge of the jungle. When Flores' love interest is stung by a poisonous wasp, Sarone offers to help them, but his motives aren't entirely pure. Soon, he takes over the entire ship and convinces the members to go with him on an expedition of stupidity against a giant anaconda.
The reason Anaconda falls in the B-movie category is because it is based on a plot that involve alliances and conflicts being formed that don't make sense. Not only do these happen in the most illogical of manner, but there's no character development to justify this. For example, why would Flores' sound operator side with Sarone?
But if I thought about it too much, I'd be missing the point. The film is really about the anaconda and Sarone's fight with it. As such, Jon Voight does a great job as the villain with a promise to return at the end. The cast includes some other big (with a capital B) names like Ice Cube, Eric Stoltz, Owen Wilson, and Kari Wuhrer, and they do a passable job getting eaten by the gigantic snake.
What stands-out the most is the special effects, which really make the snake as convincing as any I've ever seen. There are some spectacular shots of anacondas performing death-defying stunts to catch their prey. That alone makes Anaconda worth a rental.