10 Terrifying Moments on Unscripted TV

Whatever your opinion of "Jersey Shore," your heart will race (and blood will boil) when Nicole "Snooki" Polizzi, a female cast member, gets punched in the face by a male high school gym teacher.

The punch itself isn't shown (though it's described in detail and was featured in advertisements for the show), but the episode is still guaranteed to earn your ire through the facts surrounding the attack. Unprovoked violence is scary and maddening whenever it happens, but the assault on Snooki is especially frightening, considering the reality star is 4 feet 9 inches tall, and her accused attacker, Brad Ferro, is a tall, muscular man who knocks her to the floor after stealing her drink.

"Jersey Shore" may not be the most cerebral entertainment, but it doesn't take a genius to know what happened to Snooki was wrong, and it's frightening whenever an event like this happens -- regardless if it makes the final cut or not.

Bear Grylls knows something about fear. After all, it's his job to place himself in life-threatening situations. He uses his wits and survival experience to entertain and educate the viewers of "Man vs. Wild."

Grylls has faced countless dangerous situations, but we're treated to a real nail-biting moment when he crosses a murky, alligator-infested river. Grylls explains that alligators can easily mistake swimming humans for turtles or other common prey, and that he'd be virtually powerless if one of the supersized reptiles were to strike. When he dives in, knife tightly clutched in hand, Grylls is visibly frightened. Though he makes it to the other side in one piece, it's perhaps the scariest segment of a show built on outdoorsy thrills.

A show about truckers? Eh. A show about truckers navigating giant loads across ice? Now, that's something people tune in to see. The Alaskan routes these truckers drive have precipitous, 1,000-foot (300 meter) drop-offs. Winding, ice-covered roads and dangerous environmental conditions all combine to make "Ice Road Truckers" a can't-miss series for thrill seekers and couch potatoes alike.

Any time you mix icy roads with heavy vehicles, you're going to have at least a few scary moments, but when you add the imminent threat of avalanches, the show becomes downright terrifying. That makes it hard to pick a single moment from this series as the most frightening. Watch as drivers caught in an avalanche's path are powerless in the sea of snow that carries their trucks down the mountain. As they grapple with danger, you can see crosses lining the road, marking spots where truckers before them were caught in the snow's unstoppable path.

Despite some close calls, none of the show's stars have been caught by an avalanche yet, but watching them navigate the danger zones is heart-stoppingly scary.

Many people featured on "Confessions: Animal Hoarding" have dozens or even hundreds of animals. Filth, disease and malnutrition are all common occurrences in their homes. So, you might assume the story of a man with 19 dogs would be sad but not so scary. You'd be wrong.

Shane, a single dad with full-time custody of his daughter, has 19 pit bulls, most of whom are so aggressive they have to be chained and separated from one another 24 hours a day. Shane believes he's on a mission from God to save ailing members of the breed -- even though their violent behavior poses a significant threat to his daughter, himself and the other members of his family. His dogs have killed other pets, and they fight one another frequently. Shane seems to prioritize the pit bulls over his family, and he spends the majority of his limited funds on dog food. It's a scary situation, made even more frightening by his disregard for the health of all parties involved, including the dogs.

As any "Survivor" fan can tell you, the show's not a competition for weak-willed players (or viewers). There have been several medical evacuations in past seasons, but the collapse and subsequent evacuation of Russell Swan in "Survivor: Samoa" was perhaps the most frightening moment in the show's history.

Swan's troubles begin during a team challenge. He starts wobbling while standing in place, and just as it becomes obvious that something is wrong, he passes out. Medical personnel rush in and report that his blood pressure is extremely low. After several minutes of resting, his situation doesn't improve. But it's not until he tries sitting up that things get really scary.

While the emergency monitoring equipment screeches warning sirens, Swan's eyes turn glassy and lose focus, and he becomes completely unresponsive. The situation lasts only a few seconds, but it's clear that something is seriously wrong with him. Swan is evacuated off the island.

After leaving the show, Swan makes a full recovery, but for a few terrifying moments, his fate was uncertain. That's about as scary as reality TV can get.

Regardless of your stand on certain environmental issues, "Whale Wars" is an exciting, often terrifying show. The Sea Shepherd Conservation Society has antagonized and confronted the Japanese whaling fleet for years, but in the third season of the show, aggression really heats up. Until the episode "Sliced in Two," all attacks by both parties are nonlethal, with the whalers using powerful deck-based water cannons and the Sea Shepherds opting for loud noise disruptors, spud guns and paint. But in this episode, the whalers have enough. They purposefully crash into the Shepherds' small stealth ship, the Ady Gil, cutting it in half.

For several terrifying minutes, it looks like the Ady Gil crew is lost. Their boat lies in pieces, and no radio contact can be established. While the whalers make moves to lower a small inflatable boat into the water, with the presumed intention of capturing survivors, the Shepherds act quickly to rescue their cohorts. While all crew members survive the accident, the confrontation stands as one of the most frightening moments ever captured on the open seas.

We all know the show's reggae theme song ("Bad boys, bad boys, what'cha gonna do, what'cha gonna do when they come for you?"). But it's easy to forget just how bad the suspects on "Cops" can be -- and how dangerous it is to be a police officer.

The season 20 premiere of "Cops" begins with in-dash footage of a suspect shooting an officer, and the episode opens with the subsequent on-foot police chase. We follow Officer Caleb Lenz, who, along with a team of other officers and a trained police dog, effectively and efficiently apprehends the suspect. The police officers take every proper precaution, and although no other officers are injured, we can see the fear and resolve in Lenz's face.

Chasing down a brazen shooter is as real as it gets, and it's clear that Lenz and his men are putting their lives on the line. It's a thrilling, terrifying and -- after the suspect is apprehended -- extremely gratifying moment of reality TV that reminds us why this groundbreaking show is still on the air after all these years.

Fighting the battle of the bulge might not sound that frightening, but during the eighth season premiere of "The Biggest Loser," the usually uplifting show got supersized scary.

For the first challenge, contestants are asked to race the final mile of their journey to the ranch where they'll be living. This wouldn't be much of a test for contestants even a few weeks into the program, but for two new recruits, it's downright dangerous.

One woman collapses 100 feet (30 meters) before the finish line and has to crawl on her hands and knees to the goal. After crossing, she becomes completely unresponsive and has to be airlifted via helicopter to a nearby hospital. Another contestant, an older man, has health-related complications after the race and is strongly advised by the show's medical staff to go the hospital, which he does. Both contestants eventually return to "The Biggest Loser," but their ordeals add a somber note to the tone of the show.

You need sturdy sea legs and nerves of steel to watch "The Deadliest Catch." Near-death experiences are commonplace with surging waves, freezing temperatures and multiton equipment tumbling haphazardly across ships. Viewers are treated to a new form of terror and anxiety in a third season episode titled "The Unforgiving Sea," which focuses on near misses and close calls at sea, as well as the unfortunate fate of far too many fishermen.

In the episode's opening moments, we get a firsthand look at the Coast Guard's search-and-rescue mission for a sunken ship's four-man crew. After finding an empty survival suit and life raft floating forebodingly in the frigid water, the Coast Guard spots a single survivor clinging to debris. He's pulled to safety, but the shaking, barely-conscious man has hypothermia, and viewers are informed that he's dying. The rescuers continue their search for survivors until they spot two dead crewmen floating in the water. The fourth crewman is never found, and though the single survivor lives to sail again, his story serves as a harrowing reminder of the mortal danger commercial fishermen face on a daily basis.

Steve Irwin, aka the Crocodile Hunter, didn't shy away from danger. The adventurer is now deceased, but he made a living poking, prodding and generally agitating dangerous beasts all over the world. Whether he was tackling snapping crocodiles or stirring up venomous spiders, Irwin made these fearsome creatures accessible to TV audiences. However, he placed himself in countless life-threatening situations to do it.

Irwin's self-acknowledged scariest moment occurs while working with a timber rattlesnake in the Appalachian Mountains. Using just a stick and his bare hands, he pulls out one of several rattling reptiles from under a rock, and squatting on his haunches, proceeds to educate viewers on the snakes' mating habits. However, his lesson is cut short when he hears the distinctive sound of a second rattle coming from between his legs. He looks down to discover another snake poised and ready to strike. While holding the first slithering specimen at arm's length, Irwin cautiously retreats.

As you'd expect, the situation is both humorous and alarming -- it's hard not to laugh at Irwin's shocked expression and cringe in terror at the prospect of this extraordinarily likeable and good-natured man being hurt.