* The "Stinky Car" myth, in which two pig carcasses were left to decompose for multiple months inside of a car in order to test if it would be possible to clean the resulting stench out. During the attempted clean-up, we don't get to see much of the car's interior thanks to GoryDiscretionShot, and only have the {{squick}}ed-out reactions of the crew to go by, but this arguably invokes NothingIsScarier as to what the inside of the car and the pigs' remains looked like.
* The Meatman is pretty disturbing in itself, but the test it's used for-- showing that a person could be crushed in a closed-dress diving suit by deep water pressure-- will haunt you for a good while. [[https://www.youtube.com/watch?v=LEY3fN4N3D8 Watch...]] if you dare.
** Made 100 times worse when you find out ''[[https://en.m.wikipedia.org/wiki/Byford_Dolphin someone actually died a similar way.]]''
* While the catastrophic failure of a water heater is spectacular to behold, the end result of what several hundred pounds of steel propelled by superheated water is capable of doing to a house, much less any poor bastard in the flight path, is made more disturbing by the fact that ''[[http://www.combustionsafety.com/secured/pdf/safetyalerts/star_spencer_lesson.pdf it actually happened.]]''
* Torture:
** A standout is the Bamboo Torture Myth, wherein someone is tied down over bamboo shoots which are left to ''grow through them''. The result of the test with a ballistic gel torso? It works exactly as the myth states.
** The Chinese Water Torture myth is this as well.[[labelnote:*]]For reference, this "myth" was to figure out whether the water torture really works as described, as it normally sounds so innocuous. In it, the prisoner is held down on a flat surface and restrained with a water dropper apparatus positioned directly above their forehead. At random intervals, a drop of water would fall and land on their forehead. Sounds simple enough, right? Even harmless. But the idea behind it is that it takes a combination of things to be effective: Prolonged exposure, usually several hours; restraints that become more uncomfortable to be in over time; a head restraint that ensures that the prisoner cannot turn away or reposition herself from the drops hitting the exact same place every time; and the randomness of the drops' timing make it impossible for the mind to anticipate the drops falling and "brace" itself for the impact; and finally that while the water itself won't cause any physical harm, the forehead has many nerve endings that make it sensitive to touch, all the more so over time as the prisoner has no choice but to focus on it, like one not feeling a mosquito bite until they notice it and it becoming aggravating and unable to be ignored once they do; all of these combined are what will make it effective.[[/labelnote]] Seeing Kari break down is brutal. Made worse because we all know she's with friends who will get her out of there the moment she makes the slightest noise. [[ColdBloodedTorture Imagine if it were real, and the people surrounding her didn't give a withered crap about her?]]
*** Possibly even more disturbing is the reaction of [[CloudCuckoolander Tory]]. Seeing such a [[OOCISseriousBusiness normally goofy and fun-loving guy so deadly serious and obviously concerned]] really drives home how unpleasant the situation must be. When poor Kari starts crying, Tory ''immediately'' gives the order for her to be released.
*** Of course it also quickly becomes an understated SugarWiki/MomentOfAwesome for Kari, because she ''stops him.'' She takes a moment to calm herself down, then continues with the experiment until the attending EMT pulls rank. Kari Byron, [[MadeOfIron Woman Of Iron]].
*** Though a segment filmed some time later (her outfit and hair style are completely different than in the test) has her talk about how unpleasant it was, and the only thing that let her go through with it ''at all'' was knowing she was surrounded by friendly coworkers and [=EMTs=] who had her safety as their top priority, and even then the memory is not pleasant, and she still had bruises on her wrists from the restraints.
* The high-speed camera also counts, particularly when showing anything biological. Unless it's Adam being slapped in the face, ''that's'' just plain hilarious.
* There are two words guaranteed to make long-time fans cringe: "Chicken Hand": several chicken thighs sewn together to mimic a human hand -- which is disturbing in itself -- to test the results of an improper grip on a revolver (holding one's thumb against the cylinder gap). It nearly severs the thigh. Worse, this is based on a real incident, the results of which they see in a photo they aren't allowed to show to the camera.
* Also ''smashing quick-frozen heads'' to see if they will shatter like glass (as shown in ''Film/JasonX''). They bring out their trusty ballistics gel again, use a similar substance for brains ...and use ''actual human skulls''. Then for even more added realism, they use ''pigs' heads''. They even say in the show that they can't show the original clip just because it was so disturbing, and have to substitute with a cheesy cartoon re-enactment.
* ''Everything about the Underwater Car myth, '''especially''' the Inverted revisit.'' Just watching Adam go down with the car is uncomfortable by itself. Imagining yourself in Adam's place, in a car that's sinking for real, is some serious nightmare fuel. Then there's the Turn Turtle revisit. Just watch [[https://www.youtube.com/watch?v=v-eK_cpTsOw this video]] of Adam detailing his experience. (Also keep in mind that Adam technically "died" in the experiment. He had to use an emergency air supply, which someone in a real-life situation wouldn't have.)
** It gets worse, it turns out Adam failed partly because there was an unexpected variable that nobody had anticipated; the car originally belonged to a smoker and the residue made the water acidic, ''blinding'' Adam on top of everything else. Congratulations smokers, the mythbusters have officially discovered a new way for your secondhand smoke to horribly, ''horribly'' kill you and those around you.
** In the second day of testing of the ''first'' experiment, Jamie told Adam that the image of him going underwater in the car [[http://www.discovery.com/tv-shows/mythbusters/videos/adam-savage-on-underwater-car/ didn't let him sleep the previous night]]. Adam too has stated several times that the Inverted Underwater Car is the scariest and most dangerous stunt he's ever done, as in this particular situation, him not panicking was the only reason the test went without incident.
* Likewise, Jamie's time being buried alive ...and the coffin starts buckling.
* Jamie turns out to be this for Adam in the NeverBringAKnifeToAGunFight tests. As it turns out, Jamie Hyneman brandishing a (fake) knife, and charging at you while inexplicably ''[[ScreamingWarrior roaring at the top of his lungs]]'' is a little bit scary.
* As stated in the "A-Z of Explosions" special, [[NothingIsScarier nothing]]. As in, when they try to blow something up [[WheresTheKaboom and nothing happens]], because this means someone has to go over and find out what went wrong and fix it, putting themselves in the potential blast radius of armed explosives.
* Though it was never actually aired, during filming of the Build Team's test of decapitating heads (using goats' heads as stand-ins), Tory mentions he finds how easy decapitation is to be particularly disturbing.
* The explosive decompression myth is proven "Busted" but as a measuring stick, they explosively decompress an airplane and blow a huge hole out of the top of it. It gives Jamie a rude reminder of how bad something like that could be if the plane is in mid-flight.
* When testing whether a human voice can shatter glass, they're first doing tests with speakers and Jamie attempts to mimic the tone that the glass made to shatter it, which comes out as this frightening, metallic noise. Adam says he had a nightmare with this kind of noise in it once.
* The "bomb baby" DIY bomb robot that Jamie builds for the "Fire in the Hole" myth. Look at the thing!
* Jamie's "Lawnmower from Hell". So over-the-top crazy that it actually ''shears its own blade off'' before they can get the high-spectacle ending they want. When was the last time that happened?
* Jamie seems to be the ButtMonkey of the final season opening shorts, but some of them get downright disturbing considering the program's demographic. The worst offender has to be the one where it implies Adam accidentally crushes Jamie in a car crusher.
* [[https://youtu.be/ziQWDnFSPt8 In an interview session with fans]], someone asked about myths they couldn't show, specifically the most disturbing one. Adam then begins telling about the time they decided to test the old adage "The cardboard box has more nutrition than the [insert sugary cereal's name here]." The experiment was simple enough: they had their control rats with normal rat pellets, Group 2 which got Fruit Loops cereal and Group 3 got pellets made of cardboard. Each group had 3 rats. They proceeded to leave the rats with their food with plans to come back and test their health stats after a set period. After said period was over, they came back and discovered Group 3 now consisted of [[MonstrousCannibalism one rat and 2 skeletons]]! College students who saw this had absolute fits in horror and absolutely ''no one'' wanted to air this experiment (although [[NightmareFetishist Adam apparently found it hilarious]]).
* For animal lovers, a couple of episodes where the team go to a taxidermist. One highlight is Adam innocently wearing a complete bear skin and showing that the taxidermist had sewn finger pockets into the paws.
* Attempts at testing the "Killer Ceiling Fan" myth started out fairly innocuously, with the tests involving a household fan showing that it wouldn't do much more to a person than just give them a few bruises. Then they test an industrial fan, showing that if you jumped into it from below it'd practically scalp you, and if you jumped into it head-on it'd slice your neck open, both of which are graphically demonstrated by the ballistics gel dummy they test the fan on. ''Then'' they try to replicate the result of the myth -- that a fan could actually decapitate a person -- by building the "Fan o' Death", a set of razor-sharp blades attached to a lawnmower engine, which utterly mangles (albeit still fails to decapitate) another dummy, and is deemed by Adam "one of the most upsettingly lethal things" they've ever created on the show.
* A malfunction during a scale test for the "border slingshot" myth results in the catapult throwing the 2kg test weight they're using back towards Jamie, Adam, and the crew, leading Adam to remark about how bad it could have been had that happened with the '''10kg''' bowling ball they intended to use for the second half of the scale test. As if to illustrate Adam's point, said malfunction happens again when they actually do move on to testing with the bowling ball. Fortunately, after the first incident they've reconfigured the slingshot so they can set it off from a distance, but the danger they could have been in is amply demonstrated when the bowling ball is launched backwards into a camera, destroying it.
* At a con, a fan asked Adam about the biggest disaster the team had behind the scenes. Adam revealed that at one point, Kari, Grant, and Tory were investigating the potential explosive properties of some common material, and what they found was so explosive and so easy to make that they destroyed the footage and [[LetUsNeverSpeakOfThisAgain agreed to never disclose what they learned]].
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