Disastrous Demonstration

In Real Life, a product's design may be rejected because it's not cost-effective to make, because it infringes on someone else's patents, because the expected market for it has diminished, or many other dull-but-practical reasons. In fiction, that's not good enough: for a product to be abandoned, something must go disastrously wrong at a meeting of investors or shareholders, or even at a press conference announcing the product's debut. This always results in the product being cancelled, even if the catastrophe has nothing to do with the product's quality or lack thereof.

A subtrope of Gone Horribly Wrong.

Comics

 * In the original Amazing Spider-Man, Dr. Octavius has problems during his new invention's demonstration, which sets him on the path to become supervillain Doctor Octopus. The movie Spider-Man 2 carried over this element of his origin-story.
 * A common event in Dilbert.

Film

 * In Rise of the Planet of the Apes, Bright Eyes escapes and rampages through the biotech company's facility, until she's shot right in front of its board of directors. The serum that'd made her intelligent is immediately shelved, even though her escape was a result of handlers' errors and her own Mama Bear nature, not the serum.
 * In RoboCop, the demonstration of a glitching ED-209 results in one of the company's lesser executives becoming Ludicrous Gibs. The ED design is sent back to the drawing board in favor of Robocop.
 * In Splice, the transgenic organisms Fred and Ginger tear each other apart during a live TV promotion for their creators' gene-splicing technology. The program that created them is cancelled because of the debacle.
 * In Cars 2, the Lemons exploit this trope, actively conspiring to discredit green fuels by engineering terrible wrecks during a worldwide racing demonstration by vehicles using the Allinol biofuel.
 * Young Frankenstein: Freddy introduces his monster in a song-and-dance routine, which goes fine until a stage light bursts into flame, which scares the monster into going on a rampage.
 * Something always goes wrong when introducing Kong to the general public.
 * Charlie Chaplin's Modern Times has a gag in which a salesman pitches a mechanical feeding device (to save time on lunch breaks) by testing it on the Tramp.
 * In Honey We Shrunk Ourselves, Wayne's less-than-impressive presentation is implied to have lost a major deal, with the investors leaving looking dissatisfied.
 * In Meet the Robinsons, Bowler Hat Guy tries to pass Lewis' invention as his own to a corporate board. As he doesn't know the first thing about how to operate it, the meeting is a complete debacle.
 * In Young Einstein, Preston Preston steals Einstein's beer-bubble-maker and, in his ignorance, nearly nukes London in his attempt to demonstrate it.
 * In Deal Of The Century, when a UAV is launched at a military aircraft demonstration, it malfunctions and destroys the expo. The design is justifiably scrapped when these technical difficulties are found to have resulted from the drone not being water-resistant.

Live Action Television

 * One episode of Honey I Shrunk the Kids's TV spinoff featured an alternative-energy car (powered primarily by burping) that Szelinksi felt might revolutionize the industry ... however a traveler from the future warned them that something had gone wrong during its planned production, resulting in a Bad Future, and they had to find a way to stop it. It was ultimately the foul-smelling exhaust that turned investors off.
 * In a blackout sketch on The Benny Hill Show he plays a TV pitchman selling a new cleaning product; he tosses some liquid (juice?) on the wall and a man in a labcoat uses the product to clean up - except the product doesn't clean off the stain, it cleans the wall's decorative paint off while leaving the stain.
 * In The IT Crowd, Moss's prototype bra that he is trying to get investors for production has a bad habit of spontaneous combustion.

Web Comics
"General Lumberdon: That's more fireworks than the Fourth of July during a nuclear war. To think I was going to pay you to build those piles of muskrat droppings."
 * Antihero for Hire chapter "Iron Fists", where it went badly for Ichabod Bernt. His show itself had a good chance to sell, but the whole plan was far too greedy to be safe.

Western Animation

 * In the Superman: The Animated Series pilot, the "Lexo-Skel Suit 5000" is stolen by Kaznian mercenaries during its demonstration. Turns out, however, that this disaster was part of a Xanatos Gambit by Lex Luthor.
 * Also, this happen in the episode "Critters" of Batman The Animated Series (Well, technically The New Batman Adventures), in which Farmer Brown's demonstration of giant farm animals goes awry when the giant sheep he's presenting breaks out of its cage. The idea behind the giant animals was to create a means to end world hunger, but because of the incident Farmer Brown was ordered to stop his work. Which of course led to him becoming the villain of the episode.
 * Almost every Sumdac Systems prototype in Transformers Animated, from the pilot episode onwards.

Other

 * The classic cliche is the door-to-door vacuum cleaner salesman, who starts by dumping dirt (or worse) on someone's carpet to demonstrate the amazing cleaning power of his vacuum, only for something to go terribly wrong.

Real Life

 * There's a story of a salesman attempting to demonstrate the durability of the windows he was selling by ramming into one, only to break it and fall to his death.
 * A Darwin Award winner suffered a similar fate, while attempting to show off the sturdiness of the glass in his law firm's high-rise offices.
 * The original launch of the Advanced Passenger Train in the winter of 1981 was a publicity disaster from which the project never recovered.