Smash Cut

A Smash Cut cut occurs without warning in the middle of a scene and transitions abruptly to another, and is often intended to startle the audience. Very often, it goes something like this:

"Bob: I am so not going to -- [ Smash Cut to Bob doing whatever he was about to say he wouldn't do] Bob: ...Dagnabbit."

Can also be combined with Gilligan Cut, or Ironic Echo, though a Smash Cut is defined by the lack of warning that it is coming and the fact that it usually cuts someone off mid-sentence. This is also a popular technique for going to credits, or for when someone wakes up from a Nightmare, so it often overlaps with Catapult Nightmare.

Not to be confused with the 2009 Canadian movie Smash Cut, though it's entirely possible that the movie employs smash cuts in production...

Anime and Manga

 * In Mahou Sensei Negima, Chapter 83, we follow Yue briefly after she sees Negi and Nodoka off on their date. In the last two panels of the page she bumps into someone and apologises. The scene then abruptly cuts back to Negi and Nodoka, and it's not until four chapters later that we return to this scene and find out that she bumped into.
 * Neon Genesis Evangelion uses this quite a bit, usually skipping from an Eva having its ass whooped to a replay of the damage.

Film

 * Employed in many horror movies, especially in Screamer Trailers.
 * The movie War had these just about every second to the point where you say "This is ridiculous!" ten minutes into the movie.
 * A Serious Man: When the truth is found to be lies, and all the joy within you dies...
 * The ending to Inception:
 * Used any time Jason puts together a costume in Mystery Team.
 * Used comically in John Carter.

Live-Action TV
"Destiny drops out of FTL. Eli (in the control room): All right, this is ridiculous. Jumping back and forth without any warning is completely-- Eli (back in his hotel on Earth): --unacceptable! [looks around] Seriously?"
 * An Angel episode had Wesley happily declare "We're winning!" during a battle. Smash Cut to the aftermath of the battle and the group tied up.
 * In fact, something like this happens in almost every episode of Angel.
 * Joss Whedon does another one in Serenity, when we cut from River being told to "lie down" to her having a needle shoved into her forehead in a lab. Joss admits on the commentary track that much of the camera work in the first few minutes, which includes several Smash Cuts and Hard Cuts, are designed to show River's fractured mental state, and by contrast when we first see the titular ship it's done in a Oner to establish a sense of safety.
 * Yeah, Joss Whedon loves these. A particularly heart wrenching example is in the Buffy episode "Selfless" which goes from Anya singing an upbeat song (during the Musical Episode) about how much she loves Xander to
 * Several more appear in "The Body", cutting from.
 * A more light-hearted version from the Musical Episode is cutting from the midst of Tara's highly-suggestive love song ("You make me--" (complete)) to Xander hinting Tara and Willow have slipped away for some nookie.
 * The Lost episode "The Constant" uses Smash Cuts to show Desmond's jarring transitions between 1996 and 2004.
 * A Stargate Universe episode had body-swapping communications devices "blink" as a result of the spaceship carrying them going in and out of FTL. This resulted in people who were temporarily borrowing other people's bodies thousands of light-years away, getting jerked back into their own for a few seconds with no warning at all.

""AY DIOS MIO!!!""
 * Lampshaded in 30 Rock episode "Smash cut to".
 * Happens at the end of the Doctor Who serial Revelation of the Daleks when the Doctor is telling Peri where he'll take her for some peace and tranquility. "I'll take you to-" (closing credits).
 * In an episode of The George Lopez Show, Benny vows do something horrible to George for rigging a productivity contest. George thinks she's bluffing. Cut to George crying over his broken golf clubs.

Video Games
"Dangeresque: I solved the kidnapping case, Renaldo! She was kidnapped by a monster with a broken heart. Renaldo: That's the dumbest— {Jump cut} Dangeresque, you're a genius!"
 * In the Strong Bads Cool Game for Attractive People episode Dangeresque 3: The Criminal Projective, this happens when Strong Bad tries to edit around Coach Z's bad acting. It fails:

Web Animation

 * Happens fairly often in the Homestar Runner series, notably the Strong Bad Emails.

Web Original
"[Nick sitting at a computer.] Coach: Aaaaaaaggghhh!! [Coach blasts a hole through the wall with flames shooting from his groin, frying Nick into a charred husk.] Nick: Coach...you do that again, and I will bury you alive. Coach: AAH--! [Coach is barely holding it in.] Nick: Coach...! Coach: Eeyaaaaagghh--!! [The entire building explodes, and we smash cut to Coach's hand sticking out of the ground, giving the middle finger.]"
 * Another Joss Whedon example in Dr. Horrible's Sing-Along Blog - a particularly bleak one and heartwrenching one at the very end that will have you desperately waiting for another scene. There isn't one.
 * A scene from G Mod Idiot Box uses one of these, when Coach suffers from a volatile form of gonorrhea.

Western Animation
"Bender: Wait. You mean people will pay good money for romance? Hmm. I think I have a scheme so deviously clever that I-- [Smash Cut to courtroom and judge banging his gavel] Judge: $500 and time served. Bender: Stupid anti-pimping laws!"
 * Every episode of The Venture Brothers ends with a smash cut into the ending credits.
 * In Futurama, we have the producer's favorite smash cut ever from the episode "Put Your Head on My Shoulders":

"Nudar: Tough times earth chumps. We're repossessing your TV. Seems you can't afford it now that you're unemployed! Zoidberg: We're not unemplo- (Cut to the crew being kicked out of the office)."
 * Another example happens right at the end of "How Hermes Requisitioned His Groove Back", when Zoidberg starts to sing his song and it smash cuts to the credits. We then hear Zoidberg sigh.
 * Most of "Time Keeps On Slipping" is held together entirely by Smash Cuts, with the twist that the characters don't remember what happened in between.
 * From Bender's Big Score

"Bender: That's righ-- monogamous? (Cut to Bender on a beach somewhere with two fembots.)"
 * In "Proposition Infinity", Amy and Bender have a torrid and illegal romance. They spearhead a campaign to make robot/human relationsihps legal, and actually win. Amy says now they can openly have a serious, monogomous relationship.

"Helga: "There is no way I am taking the subway!" [Cut to Helga and the gang in the subway station.] Helga: "...I can't believe I am taking the subway.""
 * Batman the Brave And The Bold: The new Justice League, still a Ragtag Bunch of Misfits at this point, is about to go take on Darkseid. Martian Manhunter encourages everyone with a Rousing Speech...and we cut to everyone chained up in Darkseid's dungeon. While he got to finish his sentence, it was sudden and unexpected. And hilarious.
 * From Ponyville Confidential: Rarity, at Sugarcube Corner, is dismissing the idea that Sweetie Belle is Gabby Gums. "How could you say such a thing, Twilight?! [Sweetie Belle] is the most innocent, most lovely-" *cut to Rarity, back home, finding in Sweetie Belle's saddlebag* "MOST EVIL PONY IN EQUESTRIA!
 * Happens a lot to Helga and Arnold on Hey Arnold!!.