Placebotinum Effect

Applied Phlebotinum often works in ways that seem like they should be impossible. Occasionally, however, it really is impossible. The phlebotinum doesn't actually work in the way it's supposed to; instead, the psychic or reality-warping powers of its creator make it act as they intended.

This may be an unconscious effect; in this case, the creator will think they really are a genius inventor. It may be conscious, and that's just how their powers work. Either way, they're limited to what they think will work, or what should work -- even if it wouldn't actually work once physics had its say.

See also Clap Your Hands If You Believe, Magic Feather, Magic Powered Pseudoscience.

Comic Books

 * In Alan Moore's Tom Strong comic, there's a flashback in which the villain has a phlogiston machine. In the present day, Tom and the villain briefly discuss how it's now known that phlogiston doesn't exist, yet the machine worked back then (no conclusion is reached as to why).
 * An issue of Simpsons Comics reveals that most of Dr. Frink's devices work on this principle, and thus break down when his new assistant starts questioning his logic.
 * In Absolution, the villain Technocrat creates devices which defy the laws of physics. They only function within a mile radius of him, and stop permanently once he dies.
 * At one point, Flash villain, the Weather Wizard, discovered that his Weather Wand did not actually work and that the weather control powers were his own.
 * Actually in earlier comics he really needed the wand, making this either a case of Retcon or him being with the wand for so long he absorbed its powers.
 * In the Blue King run of the City of Heroes tie-in comic, Horus's technology turns out to have been this.
 * Shade the Changing Man is made of this. The madness vest does not work that way, until Shade wants it to, and after it integrates with him, he never mentions it again. His angel trap and similar machines are collections of clutter thrown together at random and shouldn't work, except that they're Crazy Enough to Work. The crack in the sidewalk in Times Square is nothing more than that until Shade decides to move in and explore it. And the "metang" Shade's hero suit is made of doesn't even exist until he decides to fashion such a suit, with the properties he supposes something like metang would have; he simply Ass Pulls it with the power of madness.

Film

 * In The Matrix Neo has to believe he can manipulate the laws of the matrix before he can actually do anything superhuman.

Literature

 * The abilities of several of the characters in the Wild Cards novels work this way. One case mentioned involved a mad scientist who seemingly created a highly advanced robot. However, when the robot was cracked open, it contained no electronic or mecahanical components at all; just a collection of random junk. In this case, the Meta Origin is a virus that induces specialized Psychic Powers.
 * Cranston, a WWII Mad Scientist in the backstory of the Temps universe. His giant robot is unaffected by a character with psychic control of computers because "he never liked Turing, and used entirely different principles". He died when he sucessfully split an atom with a hammer and chisel.
 * Flight in the Hitch Hikers Guide to The Galaxy universe works this way. It only continues to work so long as you don't think about how completely impossible it is.
 * In the Xanth book Ogre, Ogre, Smash Ogre get hit with an Eye Queue that makes him smart (ogres are usually dumb) and suddenly is coming up with complex and ingenious plans. In the end, he discovers that the Eye Queue vine doesn't actually make you smart, it makes you think you're smart - and it lasts much less time than he thought it did. The usual effect is acting pompous with Delusions of Eloquence for a few hours, and Smash was actually smart all along.
 * Another Xanth book establishes that the Placebotinum Effect is one of the fundamental laws running Xanth, and the reason ogres have a reputation for stupidity is that they have a reputation for stupidity. When characters drop their prejudices, suddenly ogres talk and act like everyone else.

Live Action TV

 * "Where No One Has Gone Before", an early episode of Star Trek the Next Generation, had a scientist try to upgrade the engines on the Enterprise. It turned out that his upgrades were (nearly) useless, but his assistant had psychic powers that were activated by the belief of the crew, enhanced because they warped to a section of the universe where reality was more susceptible to thought
 * In an episode of News Radio, Joe creates an intelligence-enhancing potion and tests it on Matthew. The results are spectacular, quickly turning Matthew into the intellectual "Smatthew" (smart+Matthew) who is so smart that he can speed-read four books at once (two of which were upside-down. "Have you ever tried reading four books at once?") Unfortunately, it wore off after "Smatthew" became smart enough to realize it was just a placebo and he therefore only imagined he was getting smarter.

Tabletop Games

 * In Warhammer 40000, pretty much all Orkish technology works this way; any Orkish technology more advanced than a basic firearm or an internal combustion engine won't work for anyone else.
 * Many of their more advanced "shootas" merely have some bullets and gears inside them, and it's their Psychic Powers that actually make the weapons work.
 * Orkish tanks go faster when they're painted red. There's no scientific reason, but the Psychic Powers of the Orks make it so.
 * Their ships are meteors with rockets on them. It works because nobody told them it shouldn't.
 * In Deadlands, Junkers from Hell on Earth work on the fine inventing principle of "Hell, that's close enough." Basically, they duct-tape together a bunch of parts that are kind of like what they need, then invoke the power of the technology spirits to make all the separate parts function like they "should".
 * In Mutants and Masterminds' Paragons setting (possibly as an homage to ''Wild Cards), several paragons create "ACME devices", which are really expressions of their power, and are almost always unreproducible.
 * Not only is this how magic works in Mage: The Ascension, but it's heavily implied that most modern technology works only because enough Muggles are convinced that it works.
 * More accurately, reality works like this. Tradition mages depend on a focus or foci to use their magic, but as their mastery of the arcane increases they realize their power comes from within and can dispense with props and rituals. It's implied Technocrats, so utterly devoted to "Enlightened Science", always need an apparatus, regardless of their ability.
 * This is one possible explanation for how mad science works in Genius: The Transgression.
 * In Rifts, the various superpowers of Crazies result from brain implants. Progressing neural degeneration can result in them believing that their powers come from sunlight, asparagus, etc.
 * In Magic the Gathering's Time Spiral Cycle, the local Gadgeteer Genius Venser has spent years developing a teleportation device that he calls an "ambulator". He finally manages to get it working. And it really does work, but pretty soon he's shocked when he discovers that, thanks to his latent planeswalker spark, he can teleport just fine without it.

Video Games

 * In City of Heroes, The PsychoChronoMetron relies on an interesting variation of this trope; while it originally worked by using psychic energy to alter the timeline and change reality, it is eventually disabled by not only unmaking its own history, but altering reality so it could no longer work, just in case anyone else reinvented it. It's hinted that the device also empowered the people who used it in the past to make such reality-altering changes, retconning itself into a Placebotinum Effect Magic Feather.
 * Brave Soul has one of the clients send you after a supposedly magic flute that can charm animals. The flute turns out to be an ordinary flute and it was the owner's charisma that charmed the animals instead. The client isn't pleased.
 * In Mana Khemia Alchemists of Al Revis, Alchemy requires the use of a mana, essentially a spirit that lends it's power to help the transmutation. However

Web Comics

 * Narbonic. The many mad scientists running amok in the book have to pay attention, at least somewhat, to the laws of physics.
 * Magellan: Gizmo Girl / Gizmo Woman created impossible gadgets.
 * Homestuck: Rose believes her magic to come from her eldritch knitting needles, but it is actually her innate power as the Seer of Light.

Web Original

 * Whateley Academy, being a somewhat Trope Overdosed Super-Hero School series, has this. There are two forms of Mad Scientist -- Gadgeteers, who have the psychic ability to know exactly what tool/technology to use to create a desired effect, and Devisers, who enforce their own reality using their inventions. Whereas Gadgeteers have to follow the laws of physics, Devisers definitely fall into the Placebotinum Effect category -- other people cannot recreate their devises, and they tend to fall apart if someone not the original inventor uses them.
 * On the plus side, at least Devisers aren't vulnerable to being told their machine doesn't work. Most of the time.
 * In Unreal Estate, . It takes the protagonist a while to figure this out.
 * In Dave Van Domelen's online shared writing universe ASH, lots of Superhero gear is like this, due to the fact that all super-powers are variations on an ability to break the laws of physics. At least one story mentions "inventions" that have nothing but a drawing of circuitry inside.