When high school nerd Peter Parker was bitten by a radioactive spider, he acquired a number of new abilities, including superhuman strength, speed, reflexes, and agility. He can even crawl on walls. But these are all abilities shared by or even inferior to that of other Marvel superheroes. What makes Spider-Man unique is his spider-sense, the uncanny ability to detect danger.

His spider-sense functions as a sort of "sixth sense." It's often been described as a short-term precognitive power that alerts him whenever danger is present. This ability has gotten him out of countless jams and will surely continue to do so in the future, even though there will always be times where he's forced to survive without it. Peter Parker's spider-sense is a lifesaver for sure, but how much do we really know about it? We were told in the past that Spider-Man received it from the radioactive spider bite, but is it really as simple as that? What else don't we know about this mysterious yet invaluable power? Let's find out by taking a look at 15 Things You Didn't Know About Spider-Man's Spider-Sense.

15. It's often overestimated

Punisher kicks Spider-Man from Marvel Comics

Where would Spider-Man be without his trusty spider-sense? The truth is, he'd be dead. He would have been killed way back in 1963 when he first needed it to survive. He uses it to dodge bullets, punches, lightning bolts and Doctor Octopus' metal arms. Since Spider-Man doesn't possess the martial arts skills of Captain America, Iron Fist, or Daredevil, spider-sense is his only defense when facing superpowered enemies.

We've seen Spidey accomplish some pretty amazing feats with his spider-sense. We've even seen him take down a Herald of Galactus. Plus, he's gone up against the Hulk without getting beaten to a pulp. And it's all thanks to his spider-sense. Because of its usefulness, it's easy to overestimate its effectiveness. Spider-Man's spider-sense is far from foolproof. If he's fighting someone who happens to be much faster than he is—such as Quicksilver or Speed Demon—he'll get clobbered before he can react. Also, if Spider-Man is facing multiple threats at once he'll feel his spider-sense tingling constantly, keeping him from knowing exactly how to respond. These "multiple threats" come in the form of several assailants at once, or it could just be one extremely skilled martial artist with various ways of inflicting pain. Though we see Spider-Man constantly dodging attacks, we also see him get punched quite often, which means his spider-sense can't save him every time.

14. It's always active, even in his sleep

In Amazing Spider-Man #141, a criminal posing as Mysterio came up with an ingenious plan to defeat Spider-Man. Part of the plan was to hit Spidey with a gas that would put him to sleep. The gas worked, and knocked Spider-Man from the edge of a roof. But his spider-sense started tingling before he could hit the ground. This woke up him just in time to save himself from what would have been a fatal fall.

To a villain who knows Spider-Man's secret identity, it might make sense to attack him when he's sleeping, but no, even that won't work. His ability to detect danger doesn't have an "Off" switch. It can trigger at any time, even when he's in a deep sleep.

If he's been severely stunned, his spider-sense still manages to alert him to an incoming threat. So even when Spider-Man himself is out of commotion, his spider-sense is putting in overtime to keep him safe.

13. It helps him protect his secret identity

Spider-Man's spider-sense is essential to his entire way of life. Not only does it protect him from immediate threats of danger, it also warns him of a completely different kind of threat: the discovery of his secret identity. His spider-sense somehow knows that if his identity is in jeopardy, so is his life. His spider-sense also triggers in the presence of security cameras, and is largely responsible for Spider-Man's ability to maintain his secret for all these years.

When J. Jonah Jameson hired Mac Gargan—who would later become the Scorpion—to tail Peter Parker, Peter was able to sense Gargan's presence, even though he wasn't trying to kill him. He somehow knew that Gargan was a threat to his secret. If he hadn't caught Gargan following him, he could have been caught changing into his Spider-Man costume. Since then, plenty of others have tried following Peter in hopes of learning his connection to Spider-Man, but without finding a way to bypass his spider-sense, it's impossible.

12. Some characters are immune

Spider-Man's spider-sense is an invaluable asset when fighting some of his most dangerous foes like the Green Goblin or Rhino, but against some enemies, the ability is practically useless. Because of the mental link through the symbiote, Venom is immune to its detection, a discovery that rattled Spider-Man during their first fight. This is one of the many reasons Venom is one of Spider-Man's toughest adversaries. Other villains related to the symbiote such as Carnage and Toxin have also displayed a similar immunity to the spider-sense.

Clones of Peter Parker like the Scarlet Spider and Kaine can't be detected by spider-sense because they share the same DNA. For the same reason, their own Spider-Senses can't detect him either. It should be noted that though Spider-Man himself cannot detect Venom, the Scarlet Spider, on the other hand, can. It would appear that Venom isn't immune to Scarlet Spider's spider-sense because the Scarlet Spider was created before the symbiote first bonded with Spider-Man.

11. Spider-Man can detect cosmic threats

Over the course of Spider-Man's crime-fighting career, we've seen him respond to threats based on how severe they are. He can usually tell how much danger he's in by the intensity of his spider-sense. A punch from the Hulk would trigger with more intensity than a punch from the Green Goblin. When Thanos used the power of the Infinity Gauntlet to destroy half of the universe, Spider-Man's sense of danger was off the charts, causing him to feel like his head was about to explode.

When Peter Parker was being followed by a mysterious man, his spider-sense was going wild but he wasn't sure why. He soon discovered that the man was the cosmic being known as the Beyonder, the same entity who whisked the heroes of the Marvel Universe away to fight on Battleworld. The Beyonder meant Spider-Man no harm and proved that he was only interested in learning about life. Spider-Man had been alerted to danger not because Beyonder was going to hurt him, but because of the destruction Beyonder could possibly cause to the universe.

10. His spider-sense was transferred to Namor the Sub-Mariner

After a brief tussle with Namor the Sub-Mariner in Amazing Spider-Man #214, Spider-Man and Namor were attacked by the Frightful Four, led by Namor's Atlantean enemy, Llyra, and the Wizard. The Wizard used a powerful device to surround them in a "psycho-transference field" which transferred the Spider-Sense ability from Spider-Man's head to Namor's. The switch went unnoticed by the pair at first, and after the Frightful Four escaped, Namor soon discovered a buzzing in his head that was slowly driving him mad. Not able to understand what it was, Namor handled it less gracefully than Spider-Man had and was eager to be rid of it.

Meanwhile, Spider-Man was easily ambushed by the Frightful Four due to his inability to sense danger. When Spider-Man realized what had happened to Namor, he helped Namor use the spider-sense guide them into finding the Frightful Four. Spider-Man and Namor defeated the villains and had Reed Richards use a machine to restore them both to normal.

9. Without his spider-sense, he had to wear special armor

After Spider-Man seemingly lost his spider-sense, he found himself in a battle with a villain called Massacre when he got shot in the stomach. A conversation with Paladin made Spider-Man realize how vulnerable he was without his spider-sense. Spider-Man went to Horizon Labs to work on a solution to his problem. Spider-Man donned a new suit of bulletproof armor to defeat Massacre. Calling it his "Spider-Armor," Spider-Man wore it a few times before having to build a new and improved version called the "Spider-Armor MK II." Spider-Man had to build a third suit to fight the Sinister Six.

The "Spider-Armor" invention is not the first example of Spider-Man using a metal suit to fight supervillains. He did it in Civil War when Iron Man designed his "Iron Spider" armor. Spider-Man usually prefers not to use armor because of how much it negates his mobility, but without his spider-sense, it stopped being a liability and became a necessity.

8. He had to replace his spider-sense with martial arts

Shang-Chi teaches Spider-Man martial arts in Marvel Comics

Losing his spider-sense dramatically affected Spider-Man's fighting ability, and replacing it with armor didn't work as well as he had hoped. Acting on the advice of Madame Web, Spider-Man turned to Shang-Chi, the Master of Kung Fu, for help. After sparring with Shang-Chi, Spider-Man used his new knowledge of martial arts that he gained from Shang-Chi and combined it with the combat training he received from Captain America to create his own fighting style. He called it the "Way of the Spider."

Complimented by his superhuman strength and agility, the Way of the Spider has proved to be an extremely potent fighting style that he was able to use to defeat Spider-Woman in hand-to-hand combat. It should be noted that prior to learning the Way of the Spider, Spider-Man was unable to defeat Spider-Woman.

The eventual return of his spider-sense gave him a tremendous boost to his already-exceptional fighting skills.

7. He can navigate while blind

Spider-Man and Daredevil from Marvel Comics

A story-arc beginning in Spectacular Spider-Man #26 saw the wall-crawler get hit in the face by an optic blast from the Masked Marauder. The blast cost Spider-Man his eyesight, causing him to wander around blindly until he fell from the edge of a building. He was rescued by Daredevil, who helped Spider-Man use his ability as a radar sense much like his own ability. Spider-Man was able to move about while relying on his spider-sense to tell him where he needed to go. This new skill allowed him to beat Masked Marauder without the use of his eyes.

When Spider-Man regained his sight, he discovered that his spider-sense had been amplified by the experience. His spider-sense had become heightened to a new level, making him more formidable than ever. His brief time as a blind superhero has proven to be a useful experience, as he has since used his spider-sense to navigate through dark areas on multiple occasions.

6. Spider-sense is mystical in origin

A few years ago, Spider-Man battled an immortal serial killer known as Morlun who thrives off the lifeforce of his victims. His victims are called "totems," people mystically connected to an animal spirit. Spider-Man's encounters with Morlun led him to the realization that he too was a totem, meaning that his powers were more than just scientific. They were mystical. As it turns out, there are many totems just like him, and they are all connected to a powerful force called the Web of Life and Destiny.

During Spider-Verse, Spider-Man learned that his spider-sense was directly linked with the Web of Life and Destiny. When the Superior Spider-Man (Doctor Octopus in Peter Parker's body) tried to destroy the Web, he hurt it so severely that the connection between the spider-totems linking them to the Web was weakened. As a result, the spider-totems lost their spider-senses.

5. It doesn't work well when he's injured, tired, or distracted

Though it's certainly true that Spider-Man's spider-sense is an ability that's active 100 percent of the time, that doesn't mean that its effective 24 hours a day. His spider-sense is a part of his mind, which means it functions just like any other part of the brain. It requires rest. When Spider-Man is tired or worn-down, his spider-sense loses its effectiveness in battle. The same is true when Spider-Man is suffering from serious wounds. Spider-Man has to be careful not to let himself get too fatigued or else his spider-sense will become unreliable.

When Spider-Man is tired, his mind will begin to lose focus. A distracted Spider-Man can easily get himself killed. When Spider-Man is too tired to focus, he lets his mind wander so much that he doesn't even notice it when his spider-sense is going off.

While Peter Parker was wearing the symbiote costume he found on Battleworld, he began to realize that he was always tired. His fatigue was affecting him not only in his personal life, but also on the streets as "Spider-Man." His lack of focus had him so distracted that he hardly had enough time to react to his spider-sense.

4. It can be neutralized

In the mid 1960s, Green Goblin devised a plan to defeat Spider-Man once and for all. He developed a gas that temporarily stripped Spider-Man of his spider-sense. After being hit with the gas, Spider-Man was completely unaware of its effects. Green Goblin followed him and watched as Spider-Man changed into his civilian clothes. Without his spider-sense, Spider-Man was unable to detect the Goblin and had no idea that his identity was in danger. This was an iconic moment for both Spider-Man and the Green Goblin, as this was the incident that made it possible for the Goblin to learn that Spider-Man and Peter Parker were one and the same.

This was not the first time the gas has been utilized as a weapon against Spider-Man. The gas later fell into the possession of the Hobgoblin. Other characters have also gone to great efforts to create tools and gasses that neutralize the effects of spider-sense.

3. He can detect the radio frequencies of his spider-tracers with his spider-sense

While still in high school, Spider-Man's aptitude in science helped him to discover a way to track his villains using a device of his own design called a spider-tracer. A spider-tracer is a tiny, electronic device that is programmed to send out a radio signal. He could secretly place these spider-tracers on his enemies and find them later with the use of a small portable receiver. While looking for Doctor Octopus, Spider-Man reached another discovery: he didn't actually need the portable receiver. He could find his spider-tracers with his spider-sense. Apparently, his spider-sense was capable of picking up on the frequencies emitted by the spider-tracer. So to find an enemy, all Spider-Man has to do is plant a spider-tracer, and let his spider-sense guide him to his target. His spider-sense will buzz louder the closer he gets to the tracer.

Spider-Man also gave Mary Jane a necklace containing a spider-tracer so that if anyone were to ever kidnap her, he could find her with the help of his spider-sense.

2. It can be used against him

Spider-Man never would have made it in the superhero world without his spider-sense, but as many times as it's saved his life, it's equally capable of ending it.

In the 1970s, the Punisher was hired by the Jackal to kill Spider-Man, but was unable to succeed. However, in the pages of What If? #58—which takes place in an alternate timeline—the Punisher discovers his enemy's spider-sense and decides to use it to his advantage. He rigged up a dummy of Doctor Octopus with plastic explosives. Spider-Man was drawn toward it by his sense of danger, and once he came too close, Punisher set off the explosives, killing Spider-Man.

In Civil War, Iron Man used Spider-Man's abilities against him after Spider-Man defected to Captain America's side. Having already studied Spider-Man, Iron Man was aware of how his abilities worked and managed to program his own form of "Spider-Sense" into his armor, giving him the ability to react to threats just like the wall-crawler.

1. It doesn't react to his friends

Spider-Man's ability to detect danger is wired deeply into his brain to detect threats that Spider-Man perceives to be threats. When the Rhino or Electro is around, Spider-Man knows there's trouble, but that's because they're his enemies. His spider-sense won't detect danger from people who Spider-Man trusts, which would make him an easy target for someone he believes is on his side.

When it comes to people Spider-Man trusts, no one fits that description more than his Aunt May. In Amazing Spider-Man #114, Spider-Man was looking for Aunt May when he turned a corner and got clubbed on the head with a vase. The blow knocked him unconscious, but luckily none of his enemies were around to capture him.

This blow could easily have cost Spider-Man his life. You can imagine his surprise when he discovered that the person who nearly killed him was his beloved Aunt May.