So you are someone who wants more power? Well, If one is good, two must be better, right? Not necessarily. You see, some forms of Applied Phlebotinum are incompatible and attempts to mix the two will yield dangerous results. There may be several reasons for this:
- The types of phlebotinum used are polar opposites: Generally speaking, using two polarized sources of power together like that will be impossible. Light and darkness will try to engulf each other and mixing fire with either ice or water will get you water or steam, respectively. Contrast with Yin-Yang Bomb.
- They both have a failsafe to prevent this. If the phlebotina are made by the same person/group or people related to that person/group, then they would be compatible enough to work together. Thus if the combined forces are capable of The End of the World as We Know It, then chances are that they implement systems to prevent them from working properly together or just make it impossible for them to work together at all. (This is more common with technological phlebotinum.) Of course, if Failsafe Failures come into play, then watch out.
- It would be Awesome, but Impractical: The use of both phlebotina would actually make it harder to use either one to its full potential. Simple as that.
Of course, there can be other reasons why it would be a bad idea to mix two different sources of great power.
A very common version in more science-based works is drug interactions.
Compare Unstoppable Force Meets Immovable Object. When the heroes are warned of this and have to do it anyway because they've hit the Godzilla Threshold, that's Forbidden Chekhov's Gun. Contrast Phlebotinum-Handling Equipment, where one piece of phlebotinum is used to contain the other. Sometimes this is invoked to make an Obvious Rule Patch less obvious.
- Kenichi: The Mightiest Disciple has Roar-As-One. It's a technique that combines Sei and Dou Ki. While it does give the character immense power for a while, the end result will normally cripple or outright kill the user. Using the technique in short bursts helps, but using it too often in a short period of time is still not recommended.
- In One Piece, what is currently established about Devil Fruits is that, among other things, you do not eat another fruit if you've already eaten one because you'll die — it's believed to be because the "devils" inside the fruit will fight each other, causing the eater to implode. Blackbeard proves himself an exception, as he is already a user of Dark-Dark Fruit and manages to get Whitebeard's Rumble-Rumble Fruit power and even more later on — though the process of which is still unknown, but seems to have something to do with his body being abnormal.
- Batman: The Joker's trademark Joker venom is sometimes portrayed (most notably in "The Laughing Fish") as a combination of two otherwise-harmless chemicals that produces instant, smiling death. Very useful for targeted assassinations.
- Death Battle Arena: A-Train's arcade ending has him accidently doing this to himself; he decides to inject himself with Venom as a means to give himself a power boost. Unfortunately, due to the Compound V already in his system, the Venom instead permanently cripples him, meaning he can no longer be part of The Seven.
- And the Giant Awoke: The first element of Olenna Tyrell's poison is put into Littlefinger's soaps, and the second one, which makes it deadly, is in candle wisps in his room. Then an excellent medicine was used against the poison… and prolonged the agony.
- Incompatible System: Human technology is based heavily on the use of WIMP (Weakly Interacting Massive Particle) fields, which give them artificial gravity, FTL, and more. However, exposure to WIMP fields causes eezo to destabilize so violently that a few kilograms can glass entire continents.
- J-WITCH Series: It's noted in "Black and White Chi All Over" that if one of the Guardians absorbs one of the Demon Chis, even if it's the same element as their own, the demonic energy could corrupt their Aurameres, and maybe even damage the Heart of Kandrakar itself.
- Batman (1989) takes the aforementioned Joker Venom ("Smylex") up a notch. It's a binary compound with the components seeded among dozens of different personal-care product brands. This means, effectively, that brushing your teeth after using a certain conditioner could make you die laughing. Fortunately, Batman's trusty computer helps him to figure out which combinations of products will do what, which when leaked to the media foils Joker's plan.
- In The Incredible Hulk (2008), Blonsky makes Sterns infuse him with Bruce Banner's blood so that he can gain the Hulk's power. Due to his own Super Soldier Serum reacting with it, he undergoes a one-way transformation to the stronger (and uglier) Abomination.
- Reign of Fire explains dragon fire by establishing early on that dragons have glands in their mouths that produce "opposite chemicals". The dragons work kind of like a spitting cobra, spraying the chemicals at a target, and when the chemicals come into contact with each other, they react and ignite.
- Exploited in Star Trek Into Darkness when John Harrison's agent destroys the Section 31 weapons lab by dropping a ring he's wearing into a glass of what at least looks like water, causing a tremendous explosion.
- Age of Fire: Similarly to Reign of Fire above, dragons are explained to spit chemicals from glands in their mouths which, when mixed and exposed to air, ignite into flames.
- Codex Alera: This turns out to be part of the reason behind the human-Icemen war. The humans use firecrafting to stay warm in the arctic regions the Icemen inhabit, while the Icemen communicate using watercrafting-based telempathy. These two magics interfere with each other, causing irritation and discomfort on both sides and turning already tense first-contact scenarios into a series of fiascos.
- The supplementary Discworld book Nanny Ogg's Cookbook contains Lord Vetinari's recipe for bread and water — mostly a detailed explanation of how to detect possible poisons. For example, even if you think that bread and water passed their separate tests, you should remember about a case where the poison became lethal only if you ate the bread and then drank the water.
- In The Dresden Files, this is why mixing potions is not a good idea. According to Harry, potions are basically drugs (magic aside), and mixing drugs is dangerous.
- One of the Mesan assassination weapons in the Honor Harrington series is the binary neurotoxin. Neither of the two chemicals used is itself dangerous (the Mesans smuggled them past a poison detector disguised as exotic perfumes), but when they're mixed, they become an incredibly lethal nerve gas.
- The Known Space universe has the life-extension drug boosterspice. The inhabitants of the Ringworld have their own life-extension drug, but you can't take both: boosterspice is poisonous to someone who's used the Ringworld drug.
- Reign of the Seven Spellblades: In volume 1 (episode 5 of the anime adaptation), the class has their first practical class in alchemy, and Oliver notes that the recipe of the day has a lot of hidden pitfalls. He spends a good chunk of time rushing around the classroom doing damage control on his classmates' mistakes: adding an ingredient to slow a reaction after one guy puts in too much bubblegrass, then telling a girl to wash her eyes out with olive oil after she fails to cover her cauldron in time after adding an ingredient. Then Pete's potion starts sparking and smoking, and he has to flip the cauldron upside-down and dive on top of it. His quick thinking impresses Professor Darius Grenville, which gives Oliver an opportunity to get him alone and kill him to avenge his mother.
- In X-Wing: Rogue Squadron, after Imperial Intelligence Agent Kirtan Loor captures Corran Horn's friend Gil Bastra, he discovers that Bastra has been taking a drug that reacts with one used in Loor's preferred torture method to cause anything from amnesia to death. Loor attempts an alternate method, but Bastra suffers a fatal allergic reaction to the bacta Loor uses to heal him up between sessions and dies. It's later stated that Bastra had previously been exposed to a sabotaged batch of bacta which caused this reaction, though it's unclear exactly how: Loor thinks it was accidental, but the series' Big Bad, Imperial Intelligence Director Ysanne Isard, thinks it was deliberate (she calls Bastra's death a suicide).
- Invoked by Londo Mollari in the Babylon 5 episode "Ceremonies of Light and Dark", when he gives Lord Refa part of a deadly poison. It's a binary poison, meaning the two components are harmless by themselves, but if they're brought together, they are very lethal. He warns Refa that the Centauri's war of conquest needs to stop, or he'll introduce Refa to the other half of the poison.
Londo: To your health, Lord Refa.
- Burn Notice:
- In the episode "Bad Breaks" one of Michael's customary voiceovers narrates his efforts to foil a gang of bank robbers.
"Mixing medications is always a bad idea, especially when one's an upper and one's a downer. Anxiety and allergy meds together are a scary combination, and that's before you add the caffeine of an energy drink."
- In "Lesser Evil", Michael MacGyvers a makeshift incendiary grenade out of brake fluid, diethylene glycol, chlorine dioxide, "and some other stuff" (a remark added as a Hand Wave because the stated ingredients couldn't actually produce a fireball as big as the one depicted).
Victor: Someone's been to the chemical store, I see! [Michael tosses it out the car window at their pursuer. Kaboom!] I like you, have I ever told you that?
- Subverted in "Enemies Closer" when Michael builds a binary chemical bomb as part of a ploy against recurring villain "Dead" Larry Sizemore after the latter drags him into a feud with a money counterfeiting gang. The bomb is a prop, and the "binary chemicals" are just counterfeiting ink.
- In the episode "Bad Breaks" one of Michael's customary voiceovers narrates his efforts to foil a gang of bank robbers.
- In one episode of Dark Angel, out of desperation, Max uses a brain implant designed to boost normal humans to superhuman levels of performance, although the physical strain dramatically shortens their lives. With her genetically enhanced physiology, she becomes unstoppable, although due to her faster metabolism, it would have killed her in hours if the implant hadn't been disabled soon after.
- In the Firefly episode "Ariel", an undercover Simon Tam saves a patient from cardiac arrest, then tears the patient's doctor a new one for causing it. The doctor mistakenly gave his patient a painkiller that, when combined with a standard prep drug used for the patient's prior heart surgery, reacts to form a vasoconstrictor (a chemical that makes blood vessels contract).
- The Late Show with Stephen Colbert has a story about a guy who mixed cough syrup with LSD, drove his car through several fences, then hallucinated that a house was on fire and broke in to rescue the family dog.
Stephen: But his cough is gone now!
- Parodied with the page quote, when the actual names of the ingredients for an experiment are blurred out to keep from giving the audience ideas.
- When examining the Hindenburg disaster, they test the flammable properties of both the hydrogen gas and the zeppelin's metallic paint and decide that a combination of the two was probably responsible. For how dangerous the combined one was? Both were already flammable individually. When combined? It was quite difficult to get the test module to survive long enough to test.
- When they're testing a Breaking Bad method of Disposing of a Body, they accelerate sulfuric acid with some "special sauce" to make something monstrously corrosive.
- Stargate SG-1:
- The early episode "Singularity" shows that in addition to the main way naquadah is explosive, it reacts explosively with an alloy of iron and potassium (we're talking two microscopic amounts of each obliterating a whole room, including the camera on the other side of it), a fact used by Nirrti to turn a girl into a walking weapon of mass destruction.
- In "Summit", the Tok'ra unveil a binary chemical agent that is incredibly toxic to Goa'uld symbiotes: an amount small enough to fit in one's pocket can reportedly produce enough Deadly Gas to kill every Tok'ra in their current base.
- Dungeons & Dragons:
- In all editions, combining a portable hole and a Bag of Holding causes very bad things to happen, although precisely what effect results depends on which is put into which. Putting the bag into the hole sucks both into the Astral Plane and renders both items lost forever. Putting the hole into the bag opens a dimensional breach into the Astral Plane, destroying both hole and bag and sucking anything in a ten foot radius into space. Various Munchkins on the Internet have come up with ways to weaponize this that no sane DM would ever allow at their table.
- Advanced Dungeons & Dragons 1st Edition had the Potion Miscibility Table, which had a variety of results when someone drank two magic potions. The bad results ranged from mild poison to lethal poison to an explosion inside the victim.
- Exploited in Evil Genius. It turns out that pesky Super Agent Dirk Masters is hopped up on tons of illegal steroids. Giving him a dip in your Bio-Tanks causes a series of delightfully nasty mutations, turning your former foe into a Freak under your command.
- In Spider-Man: Shattered Dimensions, Juggernaut gets his hands on a fragment of the MacGuffin tablet which increases his already insane physical strength, but it cancels out his own invulnerability, meaning Spidey can take him down.
- In the Faeophobia setting, two or more spells affecting the same target results in unpredictable effects that are often difficult to reverse.
- SCP Foundation: Despite the avowed lack of canon, one consistent rule is that the Foundation is averse to cross-testing. They're happy to run all sorts of tests on one anomaly, and run all sorts of tests on another, but bringing two of them to see what happens is usually a no-no, because when two things that break reality in different ways come into contact with each other the results are impossible to predict. For example, one origin story for SCP-682, an indestructible Omnicidal Maniac with an Adaptive Ability, is that it was created in a cross-test gone wrong.
- Derek Lowe's "In the Pipeline" chemistry journal has an entire category dedicated to Things I Won't Work With. Some examples:
- FOOF, or more clinically Dioxygen-Difloride. Lowe refers to the stuff as "Satan's Kimchi"
- Chlorine Trifluoride, a substance discovered by the Nazis and then set aside because they thought it was too dangerous to work with. A better oxidizer than oxygen, chlorine trifluoride is hypergolic with just about everything and can set fire to things most would expect to be unburnable like sand, ash and asbestos.
- Trizadienyl Fluoride – as one commenter put it, there are more elegant and less painful ways to commit suicide than synthesizing this stuff or trying to work with it.
- Peroxide Peroxides – Most of us have encountered hydrogen peroxide for medical use - it's a very useful disinfectant with a foaming action that helps flush wounds. What isn't immediately apparent is that peroxide is in a solution with water and only 10% is peroxide. Take the concentration up to 70% and the stuff becomes disagreeable. At 90% and above you have rocket fuel – very unstable rocket fuel at that.
- Dimethyl Cadmium isn't an explosion risk, but it will poison you and even if you survive that you'll almost certainly get cancer.
- Hexanitrohexaazaisowurtzitane – try saying that three times quickly, and before it inevitably explodes.
- General chemistry examples.
- Fluorine is a contender for the most dangerous element on the periodic table. The number of scientists maimed or killed trying to isolate it in the later half of the 19th century is long indeed, and many of the compounds it forms are hideously dangerous and include such entries as Hydrofluoric Acid. It can be calmed down to form fluoride salts, and those are put in water to help with tooth decay, but in and of itself Fluorine is nasty, nasty stuff indeed. The CRC Handbook Of Chemistry And Physics, a real life Big Book Of Everything for scientific data, notes that elemental fluorine reacts dangerously with "everything".
- The Halogen group in general is bad news - Fluorine is just the lightest and most reactive of the bunch, but Chlorine one spot down on the table is no joke either.
- Nitrogen compounds deserve a spot on this list. Diatomic Nitrogen is one of the most inert substances known, but it really wants to stay that way and be left alone. Tortured out of that configuration and into any one of a number of others and you get a substance that really wants to get back to being diatomic nitrogen. As a result the majority of explosives known to man are nitrogen compounds of some form or other, from nitroglycerin (Dynamite) to trinitroteluride (TNT), to modern RDX (the explosive agent in C4 and other plastic explosives). There's far more than these, but most of these compounds are hideously unstable and can explode if someone insults them in another room, which makes them useless in any application (at least until someone figures out how to stabilize them, as Alfred Nobel figured out how to do to nitroglycerin by combining it with clay).
- Hypergolic Propellants. These are materials which spontaneously ignite when mixed. One such fuel was used in the Me-163 Komet interceptors of World War II. The Apollo lunar lander used a hypergolic mixer for the ascent stage of the lunar lander to save weight and maximize reliability. Rocket motors using these compounds save on weight and the complexity of spark-gap or pyrotechnic igniters. Starting and stopping the motor is as simple as opening a valve. The drawback is the volatility of these compounds in general, creating the need for formidable extra safety measures.
- Basic laboratory safety techniques include diluting acids by adding the concentrated acid to water, not water to acid. Dissolving acids in water (especially stronger acids like sulfuric acid) causes a release of heat (technically known as "enthalpy of dissolution" or just "heat of solution"). If you have a small amount of water and a large amount of acid, the heat given off can be enough to raise that small amount of water to boiling, splattering concentrated acid in the process.
- Another example of two things that react violently is any strong acid/strong base combination, as the heat of formation can be quite high. For example, mixing potassium hydroxide with hydrochloric acid yields potassium chloride, which has an enthalpy of formation of on the order of four hundred thousand joules per mole. This is about a third higher than the molar enthalpy of formation of nitroglycerine.
- Adding pure alkali metals (such as lithium and sodium) to water produces a hydroxide of that metal, highly inflammable hydrogen gas, and a lot of heat... enough heat to cause the water to boil (spraying scalding-hot water with a caustic base dissolved in it) and the hydrogen to combust (causing sparks that can start fires). In other words, Don't Try This at Home for a number of reasons.
- As seen in the Firefly example above, some medicines can interact in ways that are harmful to the body, depending on the chemical substrates of the medicine.
- Bleach and ammonia. Both are excellent cleaning agents, but if mixed, they react and produce poisonous chloramine gas.
- Binary chemical weapons exploit this trope. Two chemicals are relatively innocuous by themselves, but when combined they produce something far deadlier.
- Binary agents in general. For a relatively low-key example, mix baking soda (base) with vinegar (acid). You get a big bubbly foamy reaction which ultimately just produces a bunch of CO2 and water, and a little bit of sodium acetate.
- ANFO is a well-known industrial explosive whose name stands for its two ingredients: ammonium nitrate (a common ingredient in chemical fertilizer) and fuel oil. Commercially available ANFO is purer, made of ammonium nitrate pellets and #2 fuel oil, but lower-grade ANFO can made relatively easily by terrorists with chemical fertilizer and diesel or kerosene, which has led some governments to outlaw ammonium nitrates and related compounds altogether.
- Mixing medications without proper medical advice isn't a good idea. For both legitimate and illicit drugs, a particularly dangerous combination is taking stimulants and depressants at the same time. This was the immediate cause of death for John Belushi, as he had taken a mixture of cocaine (stimulant) and heroin (depressant).
- The FDA publishes guidelines on the reactivity of various medications to each other which is updated periodically and distributed to pharmacists. Software suites that track a patients prescriptions are programmed to calculate these interactions and warn the prescribing doctor and pharmacists of known dangerous combinations.
- Likewise, many medications react badly to alcohol. The list of people who died from mixing alcohol and pills is innumerable; one example is former pro wrestler Joanie Laurer.
- Normally, grapefruit and pomelo are popular source of fruit juices and good sources of Vitamin C. But they contain chemicals that interact with a large fraction of medications; causing the risk of dangerous underdose or overdose. This was discovered when a trial to measure the effect of alcohol on a drug used grapefruit juice to conceal the taste of the alcohol.
- With the legalization of marijuana in many jurisdictions, some enterprising stoners have sought to combine it with alcohol. This is a bad idea for multiple reasons. The first is that combining drugs is more likely to result in addictive or unsafe behavior than using either of the two alone. The second is this trope. Smoking weed after drinking alcohol can result in a much more intense high, which can be terrifying for novice stoners. Drinking alcohol after smoking weed makes it harder to determine how much the stoner is imbibing, which greatly increases the risk of Alcohol-Induced Idiocy.
- Antimatter will annihilate to form pure energy when comes into contact with anything. Currently we haven't been able to create and contain enough of it for this to be a hazard, but should that ever become possible even small amounts of antimatter escaping magnetic containment would prove catastrophic.