The movie is set in 1986, when a young Les Daniels, who is terrified of snakes, is forced to go to a wedding where venomous snakes are passed around. When he is supposed to give one of the snakes to his father, he hesitates, giving the snake enough time to bite his father's artery. His father dies in a matter of minutes.Twenty years later, in the movie's "present day", Les is still scared of snakes, and his older brother Duff teases him about it. To help him get over his phobia, Duff goes to a Native American snake proprietor, Screaming Hawk. While there, Hawk tells him about a small snake living inside a jar on his desk. The snake, called Unteka, is actually an ancient snake that grows at a massive rate and whose species had killed many of Hawk's tribe in the past. The tribe was finally able to kill all but one of them, and so Unteka is the last of his kind. Duff is given three rules regarding the snake: "Don't let it out of the jar, don't let it eat anything living, and never fear the heart of the snake." Despite being told he cannot have Unteka, Duff steals the snake for his own. Once at home, Duff accidentally breaks the jar. Les sees the snake double in size almost instantly, but Duff doesn't believe his brother when he tells him the horrific tale. That night, while Duff is sleeping, the snake eats the pet cat. The snake is now grown to almost 20 times its original size. It sneaks out into the chicken coop, killing all but one chicken, which the snake soon finishes off. When Les' mother hears the commotion, she goes outside to see what's going on, only to meet the same fate. Duff becomes scared that the legend is true and decides to ask some snake killers on how to deal with his situation. They say that if the snake hasn't yet reached full size, he could kill it by stabbing it in the head. He does so and seems to have killed the snake. The following night, however, the snake awakens and kills and eats both him and the family dog.Les returns home after a long night of drinking, only to find the place ransacked. He calls his girlfriend, Erin, who is a police officer, as well as her ex-boyfriend, Bo, the chief of police. When Les says that he just knows that his family is dead, Bo becomes suspicious that he might be the killer and arrests him. Unteka then attacks a vacationing family in the woods, killing and eating them. Erin starts to believe Les' story, but Bo still doesn't. Erin heads deeper into the woods and finds a giant snake-skin, signifying that the creature is still growing. She helps Les escape and they head over to Screaming Hawk to try to find out more about Unteka. Bo and his team finally head out to kill the snake. The enormous creature jumps at them; only Bo is able to escape. Before he dies, he comes to the homes of the snake catchers that Duff talked to earlier. They try to kill the beast, but they both end up getting killed.Meanwhile, Les, Erin, and Screaming Hawk all try to find the snake and kill it. Unteka, who is now 70 feet (21Â m) long, heads to the county fair, where Feedback is making a guest appearance. The snake kills a young couple and three stoned men before making its way inside. Unteka then kills multiple people including Fay (Les' paramedic partner). Feedback is able to hold the snake off long enough to save some people before fleeing himself. On the way into the park, the trio sees a little girl trapped in a ride. Erin is able to save her but ends up being eaten herself. Just then, Erin calls Les over walkie-talkie. They head into a haunted roller coaster ride to save Erin before she is digested. Looking around for the snake, Les looks behind Hawk. Hawk, seeing the shock on Les' face, quickly turns around and tries to stab the snake, but Unteka tosses him aside, injuring him. Les is left to kill Unteka. He allows himself to get eaten whole. The snake looks at Hawk while moving slowly towards him. Just as he is about to be eaten, the snake lets out a screaming roar of pain, moves around banging its head against the wall, and then falls to the floor dead. Les cuts a hole out of the snake's chest and, holding its heart, tells Hawk to help pull out Erin. She embraces and kisses Les and walks out of the haunted roller coaster with Hawk holding the heart of the snake.Within a few months, Les and Erin get married and have their first child, and Les has gotten over his fear of snakes.
Output: Question: When does Les understands the never fear the heart part,?, Answer: When he is eaten by the snake.