This Is Not a Floor

...It is the image of a floor.

When you have a Master of Illusion or a Lotus Eater Machine, why bother bloodying your hands or risking the victim fighting back, when you can trick them into walking across empty air? A perfect plot (bar necromancy or mind-reading) when the only evidence that points toward you, or even murder at all, rests in the mind of the deceased. Often, another character will call attention to the character's actions and unknowingly break the illusion, or the illusionist will break the illusion himself at the last instant to play with the victim's mind just to show how in control he is.

The trope name This Is Not a Floor references Magritte's Ceci n'est pas une pipe. See also Leap of Faith for a way to invert the trope.

Anime and Manga

 * Shows up twice in Paprika, first from the outside, as a character rants about "the fifth grade class with the photographic zoom lens" and runs through a full-length window, then from the inside, with the main character snapping out of it just in time to avoid going over a balcony.
 * A variant occurs in one manga of Read or Die, where the floor is in fact a lot of paper being held rigid by Yomiko's will. The building was under construction at the time.

Comic Books

 * This is part of Mysterio's M.O. in Spider-Man comics and cartoons.

Film

 * Peters of Event Horizon was killed in this fashion when the evil ship created an illusion in her mind of a bridge across an open shaft with her son on the other side, resulting in her falling to her death on the gravity chamber floor.

Literature

 * in The Dresden Files book Dead Beat pulls this on Harry, filling an apartment with illusionary flame and putting an illusionary fire escape outside the window before breaking the illusion to show that it could easily kill Harry, but doesn't want to.
 * In Going Postal: A Novel of Discworld, this happens to unsatisfactory postmasters (and, very nearly, Moist.)
 * In Point Blank, the second book in Anthony Horowitz' Alex Rider series, a murder is set up by putting a holographic elevator into an out-of-order elevator shaft.
 * In Xanth, Iris has the power of illusions, and this is one of the things she can do.
 * While Calesta, the Big Bad of the Coldfire Trilogy is incapable of hurting people directly, his illusion powers make it easy for people to not notice a real danger, or a way to avoid said danger. At one point he makes an entire city fail to notice an incoming tidal wave.

Live-Action TV

 * House MD uses this a lot, in the "patient of the week is hallucinating" form.
 * Royal Pains does a similar version, where a "haunted" client can't tell the difference between a floor three inches below or thirty feet below.
 * One case in the original CSI involved a woman who'd jumped off a high-rise apartment balcony in her bikini. She'd been hypnotized to think she was taking a dip at the beach.

Tabletop Games

 * Dungeons and Dragons 3rd Edition suggested in the Dungeon Master's guide that an effective trap would be an illusionary floor over a pit of acid.

Video Games

 * Used a couple of times in the Silent Hill series, and at least once in The Movie.
 * Used to great annoyance in some The Legend of Zelda games, most egregiously the 3D ones, in dungeons that use the Lens Of Truth or local equivalent.
 * Old gamers of the Castlevania series may remember Simon's Quest and its annoying fake floors, which can only be detected if you fell through them or if you made obssessive use of Holy Water to figure out which floors aren't fake.
 * The Mega Man games occasionally use this trick. Two examples that stand out are Mega Man 2, where they can be detected by a weapon that follows the ground, the Bubble Lead, and '9'', where there are actual enemies that fly by to create holographic platforms over pits right by the real ones.

Western Animation

 * In Spider-Man: The Animated Series, Spider-Man inverted this with one of Mysterio's holocubes by projecting a gaping chasm below Rhyno, making him panic and flail around.
 * While he occasionally does the opposite, Wile E. Coyote is known for his painting of a bridge in front of a chasm. The road runner takes the bridge, Coyote tries to chase it, rips through the picture and falls.
 * In The Thief and the Cobbler, one of the op-art tile patterns in the palace turns out to be a pit.
 * In Batman Beyond, Spellbinder uses an illusion to nearly trick Terry into walking off a cliff. He has also tricked Terry into diving off of a building by projecting a waterfall over it.