"What?" Cliffhanger

An Un Reveal executed as a Cliff Hanger.

A good cliffhanger will have you on the edge of your seat, screaming "What happens next?!"

A "What?" Cliffhanger, on the other hand, will have you on the edge of your seat, demanding "What's the cliffhanger?! What's the twist?! Why should I be excited?!" Instead of postponing The Reveal, it's been included - but phrased in a deliberately vague way for cheap suspense.

A "What?" Cliffhanger happens when a chapter ends with a shocking turn of events, but the author doesn't tell you outright what it actually is. It commonly involves abuse of the word "something", implying that the "something" will be revealed at the very beginning of the next chapter, making you wonder why the author didn't just put the shocking revelation at the end of the previous chapter for untold amounts of extra drama and suspense. Instead, we are left to wonder what the plot twist will be.

Sure, it might get you to read the next part (if it doesn't take too long to get released, or if you haven't figured it out for yourself already), but it's a lot less fun and a lot more annoying than a "proper" cliffhanger.

See Also: Cliffhanger Copout, when a creator tweaks with a story's continuity of events when resolving a cliffhanger or outright denies to follow through on a promise to reveal important information from one chapter to the next.

Not to be confused with Pseudo Crisis, which at least gives the appearance of a proper cliffhanger before getting resolved in two seconds after the break.

Fanfic

 * squirrelking's So Bad It's Good Metal Gear Solid fanfic, Fight of Metal Gears. Also, Halo: Halos in Space by the same author ends with Joe Chief on the losing side of a battle, and then he "saw something and went to it and picked it up and said "no we win" to himself." Read ahead at your own risk: The next installment reveals that the 'something' was  DUN DUN DUNNN!

Literature

 * Goosebumps was famous for doing this practically every other chapter.
 * The Da Vinci Code had a One Paragraph Chapter in which Robert Langdon and his date see a thing inside a box. Whatever the grail was, it wasn't that thing. (The thing turned out to be a cryptex, i.e., a tube that had a puzzle to be solved for it to open) In fact, done frequently in anything written by Dan Brown. It's pretty much the end of every chapter.
 * The fourth book of the A Song of Ice and Fire series, A Feast For Crows, has a scene in which one character is about to be hanged, and she says an unspecified word... and that's the last we hear of her in that book. In fact, it's the last we hear of the book.
 * This was baited-and-switched in Robert Rankin's The Hollow Chocolate Bunnies of the Apocalypse, proving there's just no limit to recursive subversion of a trope. Eddie hands something important to Jack, who asks what it is -- "it's a MacGuffin". Except we never get a better explanation than that - it's only ever referred to as a macguffin, and when it inevitably turns out to be important, what it actually does is entirely unexplained as well. It's that kind of book...
 * A Series of Unfortunate Events revelled in leading the reader to believe something only for it to be contradicted soon afterwards. Especially when the reader is kept guessing what the acronym VFD stands for, only to have it revealed several different times, and all of those times to be false.

Live-Action TV

 * Happened in the second season of Supernatural. For the first 8 episodes, Dean had been keeping a dark and terrible secret from Sam, told to him by their father and also withheld from the audience. The preview for the ninth episode showed Dean saying "Dad told me something... something about you," and Sam asking in consternation, "Dean, what did he tell you...?" Everyone got very excited that The Reveal was finally coming, even though most of the fandom was already fairly sure they had worked out more or less what the secret had to be. When the episode aired, those turned out to be the last lines spoken before the series went on hiatus for over a month!
 * From Lost: "We ain't takin the plane freckles. We're takin' the sub."
 * And of course the season three premiere, which ended by revealing Ben's name. Yeah, it was nice to know the real name of "Henry Gale," but it's really just a random name, with no significance to the story, yet it's played for Luke, I Am Your Father level drama.
 * However, this becomes something of a Subversion as well: new watchers will probably hear about Ben, but not Henry, making it a legitimate surprise for Spoiler Hounds unless they read this page.
 * From NCIS: The last episode of season 7 gave examples of this trope.
 * Several episodes of Doctor Who had this problem. Season 22 was originally shown in the UK in 45 minute chapters instead of the usual 22-25 minute episodes. When that season was shown in America, each episode was arbitrarily cut in half to fit in with the remainder of the syndication package - resulting in the story simply stopping (often in very odd places) instead of ending on a proper cliffhanger.
 * One episode of "Death to the Daleks" ends with the Doctor and Bellal about to walk into a room when the Doctor tells him to stop, pointing at the white and red tiled floor for no immediately apparent reason.

Web Comics

 * Parodied here in the webcomic Ansem Retort.
 * Done in this Sluggy Freelance strip.
 * Done much more frustratingly here. Sluggy Freelance updates daily, so nobody suspected that the cliffhanger would go unanswered for nearly three months, but that's exactly what happened due to Oceans Unmoving, a truly ambitious sci-fi chapter that revisited a long-missing character but otherwise introduced an entirely new cast.