'Pretty Little Liars' Has a Huge "A" Reveal: Here are 21 Other Insane TV Twists

Just as fans of the hit ABC series were starting to get wary of watching the pre-Island lives of the Lost castaways, the series hit the fast-forward button. Suddenly, the bearded, alcoholic Jack (Matthew Fox) we thought was in the past was meeting with Kate in the future — off the Island. What in the Dharma?! Image: ABC

We knew Walt (Bryan Cranston) was bad. After all, he had murdered Crazy 8, Tuco, and Gus. But it wasn't until we spotted the Lily of the Valley in his backyard that we realized the chemistry teacher-turned-meth kingpin had poised young, innocent Brock... and had officially broken bad. So, so bad. Image: AMC

While Izzie (Katherine Heigl) faced death following surgery on her brain tumor, a mysterious John Doe enters the hospital after being hit by a bus. He's unrecognizable, and the only thing the doctors (and viewers) knew about him was that he died a hero, saving a woman from the crash. Eventually, however, the truth is revealed — the man dying in Seattle Grace is none other than Seattle Grace's George (T.R. Knight). We were sad to lose George... but thrilled he didn't return as a ghost. Image: ABC

Previously a friend to Jason and Hoyt, Rene's (Michael Raymond-James) revealed to be a killer who attempted to murder Sookie several times. But worst of all? Dude killed a cat. Image: HBO

The HBO series is no stranger to death — just ask anyone who tuned into this past season's "Red Wedding." But, after spending an entire season following Ned Stark (Sean Bean), the show's main character, our notions of how we watch television were rocked the moment his head came off. Who would we root for? Who could we root for? And would the next one be safe? Image: HBO

It was not the most plausible twist — is Gossip Girl so masochistic that he would ruin his own relationship? — the reveal that Dan (Penn Badgley) was the titular character certainly was shocking. Especially since he has Kristen Bell's voice. Image: CW

No wonder Aaron (Harry Hamlin) is such a beloved actor — he's good at acting, in front of fans, like he's not the abusive father he really is. Not to mention killer — Veronica Mars (Kristen Bell) discovers the movie star is the man who killed her best friend, Lilly. Once his true identity is discovered, Aaron is jailed and killed himself. Sorry you can't make it back for the movie, dude. Image: CW

It was as tragic as it was necessary — after taking Buffy's (Sarah Michelle Gellar) virginity, Angel (David Boreanaz) loses his soul and becomes evil, jumpstarting a plan to summon Acadia to send the entire world literally to hell. When Angel eventually reverts back to his kind self — with no memory of what he had done — too much damage was done, leading Buffy with no choice but to murder Angel to save the world. And with a tearful apology, Buffy murders her unsuspecting boyfriend. Believe us — Buffy wasn't the only one crying. Image: WB

One of the most famous plot twists of all time, Dallas made up for a weak season of television that killed off Patrick Duffy's Bobby Ewing... by claiming the entire season was actually a dream. Image: CBS

When Phoebe (Lisa Kudrow) found the positive pregnancy test, we assumed Monica (Courteney Cox) was about to have multiple milestones to celebrate her wedding night. But to find out that it was Rachel (Jennifer Aniston), who, at that point, was single — could we have been any more shocked? Image: NBC

Someone in Pawnee was pregnant... but who? While fans wondered whether it was Ann or April who was expecting, we got something we didn't expect at all: The news that Ron's girlfriend, Diane (Lucy Lawless), was pregnant. We were shocked — the only baby we ever expected Ron (Nick Offerman) to have was a food baby. Image: NBC

Orange County's biggest wet blanket (Mischa Barton) needed to go. We just didn't expect it would happen with one season left to go... and so violently. Still, who didn't put Marissa's TV death on their Chrismukkah wish lists? Image: FOX

Sydney (Jennifer Garner) finds herself on the streets of Hong Kong, relieved to be alive after a mission. Only, when she reunites with Vaughn (Michael Vartan), she discovers he's remarried after Sydney was thought to be dead... two years ago. What's a 'shipper got to do to actually make a relationship happen, television?! Image: ABC

Poor Tom Walker (Chris Chalk). The man was killed by a brainwashed Brody, heeding the demands of terrorist Abu Nazir. Except... he wasn't. To everyone's shock. Especially Brody's. Image: Showtime

Why would sweet ol' Mary Alice (Brenda Strong) off herself in the season premiere of the ABC dramedy? Well, because it wouldn't be the first time she killed someone — the housewife offed a drug-addled woman in order to keep her child. And, as it turns out, no muffin basket could make up for that sin. Image: ABC

It was silly for any of us to assume that Violet (Taissa Farmiga) survived her suicide. After all, what would a horror series be without ghosts? Image: FX

The fact that the Carver — a killer who rapes his victims before slicing their faces — was plastic surgeon Quentin (Bruno Campos) was a surprise enough. The fact that he raped his victims without a penis (using a strap-on dildo) was just icing on the seriously messed-up cake that is a Ryan Murphy series. Image: FX

Faced with jail time stemming from a cocaine bust, Adriana (Drea de Matteo) becomes an FBI informant... and meets a tragic fate once Tony learns of her betrayal. In fact, her death was so difficult to swallow, we might never drive in the woods again. Image: HBO

When it came to Dexter's girlfriend, Rita (Julie Benz), there were no gray areas — the single mom was good, in and out. So it was all the more heart-breaking to watch Dexter (Michael C. Hall) find her murdered in a bathtub at the Trinity Killer's hands, with their newborn baby left crying in a pool of her blood. Knowing that Dexter's first memory is being found in his own murdered mother's blood... well, like father, like son? Image: Showtime

When Amanda (Liza Weil) revealed that she had an affair with the president, and promptly turned up dead, suspicions turned to the Commander-in-Chief himself. But it's soon revealed that the vice president's aide, Billy (Matt Letscher), was not only having an affair with Amanda, but was the father of her unborn child... and her killer. Seems Bill Clinton had it easy after all.

Get ready to like your own family a lot more: The mystery surrounding who killed Laura Palmer culminated in the reveal that her father, Leland, had murdered his own daughter. Sort of. A demon, named Killer BOB, had entered his soul... until Leland's death. And then it simply moved on to another victim. How's them apple pies? Image: ABC