Some of these pictures and descriptions may give away plot details that you might not want to know before watching the film.
"In the media circus of life, they were the main attraction."
This is an Oliver Stone movie, originally written by Quentin Tarantino, but disowned by him when Stone made too many changes to his screenplay. Snakes and depictions of snakes show up throughout the movie, especially images of intertwined snakes, which seem to represent the intertwined evil of Mickey and Mallory, who are the focus of the film. Mickey and Mallory are young lovers and mass murderers who go on a road trip, killing innocent people when they stop. At each stop, they leave one person alive to tell their story. These witnesses help them to become glorified by the mass media and their fans.
The film is
full of cartoonish violence and bizarre and unnatural visuals. The picture sometimes changes from color to grainy black and white or to black and white that is tinted red or green like a silent movie. We see unusual projections in some backgrounds, lots of television and movie clips, and animated sequences, all accompanied by a diverse and insanely prolific soundtrack that uses more than 70 tracks, mostly rock music. One bizarre flashback sequence is even made in the style of an old TV sit com, with a ridiculous laugh track heard in the background as we watch to Mallory's father violently abuse her and her family.
Mickey has several connections with snakes which both help him and attack him. When he escapes a prison work party by stealing a horse, one of the guards chases him on horseback, but a rattlesnake strikes at the guard's horse. The frightened horse bucks the guard to the ground, letting Mickey escape, riding towards a small tornado.
Mickey and Mallory stop their car on a tall bridge over a river somewhere in the southwest and marry themselves in a personal ceremony. Mickey gives each of them a ring with intertwining snakes on it. He cuts their palms with a knife and when they put the wounds together to mingle their blood, some of the blood falls down over the bridge and we see an animated sequence where the dripping blood turns into snakes that intertwine. Mickey later gets angry when he discovers that Mallory took off her wedding ring. He yells at her to never take it off. "Every great thing we do starts with these."
In the main snake scene, which for once is actually an important part of the plot, Mickey and Mallory, high on psychedelic drugs, are driving through New Mexico when they run out of gasoline. They wander into the home of a Navajo man and offer to trade him tobacco for gasoline. The Navajo man is sitting near a rattlesnake with his grandson. He and his grandson talk about Mickey and Mallory in their own language, and we see the word "demons" projected on Mickey and Mallory. When they see the rattlesnake, Mickey and Mallory scream in fear. The Navajo man notices that Mickey has bands on his boots with decapitated rattlesnake heads on them. This shows him that Mickey has no respect for rattlesnakes, re-inforcing the idea that he is a demon. The couple point out the rattlesnake and ask if it's a friendly snake.
The Navajo man picks up the rattlesnake barehanded, puts it on his lap, and tells a story about a woman who found a frozen snake in the snow and took it home to heal it, but when it got better it bit her on the cheek. As the woman lay dying from the venom she asked the snake why it bit her. The snake says "You knew I was a snake!" (This is the same story heard in Oscar Brown Jr.'s 1963 song "The Snake," which is based on Aesop's fable of The Farmer and the Viper.)
After telling the story, the Navajo man puts the snake outside his home and tells it "Old man, go be a snake." Mickey and Mallory fall asleep and we see that Mickey is having a nightmare about family abuse. He wakes from the dream in terror, pulls his gun, and shoots the Navajo man. He's actually sorry about the killing and Mallory yells and yells at him how bad it was to kill the man. Up until now, they seemed to have no problem killing anybody at all, but now we see they do have at least a hint of a conscience. Later, they regret killing the Navajo man so much they decide not to kill anymore, saying that love conquers the demon. (That resolution doesn't last long, however.)
Mickey and Mallory leave the Navajo's home and find a full can of gasoline. When they start to walk back to their car, they pass lots and lots of rattlesnakes lying on the ground. Mickey pours gasoline and tries to burn them, but they both get bitten by the snakes.
As far as I can tell, the Navajo man used magic to make the snakes attack Mickey and Mallory after they killed him, which makes this another example of snakes used as weapons. That makes more sense than the possibility that hundreds of rattlesnakes are just lying around on the ground at night.
The snake we see in the Navajo man's hands is probably a Red Diamond Rattlesnake. The other snakes we see on the ground appear to be a combination of real rattlesnakes and fake ones. We also see a Bullsnake striking up at the camera.
In a panic, and obviously suffering from the snakebites, Mickey and Mallory drive to a drug store looking for rattlesnake anti-venin (snake juice) to heal themselves. The drug store's neon sign even has a caduceus with intertwined snakes, but unlike the traditional cadeuceus, this one shows rattlesnakes. Inside, Mickey can't find any anti-venin. The store only displays sold out signs. Mickey attacks and kills a pharmacist who won't give him any anti-venin. He never does get any because the police have found them and they beat up Mickey in a re-creation of the Rodney King video which was made a few years before the movie was released.
There are still more depictions of snakes in the movie. There's a rubber cobra on their dashboard. We see random black-and-white shots off rattlesnakes under the opening credits and at other times. And Mickey has a tatoo on his chest that shows two more intertwined snakes.