The ANYONE CAN DIE trope has really escalated in the modern television era to the point, really, that it does feel like, unless their name is in the show's title, any character can die at any time. This wasn't always the case. The Sopranos had a lot to with the transformation, and then Game of Thrones upped the ante by taking out seriously major characters often early in their runs.
But often, even if it is a main character, you get a sense that it's coming, either because events seem to be leading in that direction (Justified season two, most of The Sopranos deaths), because casting news in the trades gives it a way (Downton Abbey, The Walking Dead) or because either the showrunner or the network advertises a major death in an upcoming episode (Sons of Anarchy, specifically last season's major death) so while the identity may be a surprise, the death itself often is not.
Probably one of the truest examples of the unexpected, "Woah! Where did that come from!" death would be the box cutter episode of Breaking Bad, when Gus unexpectedly and without warning grabbed his henchman Victor -- who was up to that point smiling -- and slashed his throat. NO ONE saw that coming, and the only reason it doesn't rank below is because it didn't involve a major character.
Those are my favorite death scenes -- the kind that come out of f***ing nowhere. These are the ten most unexpected, what-the-f*ck-just-happened deaths in television's modern era. Spoilers abound, but with one exception (the very first death, which is from Game of Thrones), the deaths in question are all at least a year old.
Robb Stark, Game of Thrones
The only reason the death of Robb Stark -- and Caitlyn Stark, and Robb's wife -- isn't ranked higher is because -- unless you were completely oblivious to the ways of the series --we knew someone was going to die in the ninth episode of the third season. The surprise -- the shocking, upsetting, devastating surprise -- was in the identities of the deceased. Book readers obviously knew, and even among those who might have surmised that someone was going to die at the Red Wedding, few would've guessed that practically everyone would die, including two of the series' main characters, two who were thought to be among the main protagonists. (The death of Ned is not included on here, if only because -- while it was surprising to see the main character die -- he was being executed, something that had been in the works since the previous episode). The unexpected death of Robb's wife was so shocking, in fact, that Jeff Garlin vowed to quit the show.
Lori Grimes Walking Dead -- People die on The Walking Dead all the time. Much of the original cast is no longer around, and Shane -- the second male lead in the series -- had been killed the season finale before. Still, it came as an unexpected shock when the lead female character -- or at least, the character who started the series as the lead female -- had to be killed WHILE giving birth. The only reason it wasn't a bigger shock was because Sarah Wayne Callies and others had suggested that Lori was a character that needed to die for the good of the overall series, so some may have expected it sooner or later, though few expected it so early in the season.
Lane Pryce, Mad Men -- Much of the shock of Lane Pryce's death came from the fact that Mad Men -- despite scores of theories to the contrary -- has never been a show about characters dying, much less major characters dying. It was a combination of the fact that the season had led us to believe that, if anyone were going to die, it was Pete Campbell, and the fact that it was so seemingly so out of character for Lane up until the episodes before hsi death. However, it ranks lower than the others simply because he had shows signs of depression, he had been written into a corner, and he had attempted suicide earlier in the episode, although I don't know if that made it more or less likely that he was going to do it again.
Joyce Summers, Buffy the Vampire Slayer -- Not a hugely major character, the death of Buffy's mom was nevertheless devastating for those she left behind. Why was it so surprising? Because while Joyce had a brain tumor, she had had it successfully removed, was well on her way to recovering, and had even found a new would-be boyfriend. Then, out of nowhere, AT THE BEGINNING OF THE EPISODE, Buffy walks in casually and finds her Mom dead.
Jimmy Darmody, Boardwalk Empire
The thing that was perhaps most surprising about Jimmy Darmody's death in the second season finale of Boardwalk Empire was that two other major characters -- Angela Darmody, then The Commodore -- had died in the previous episodes, so it didn't feel like another character would die. The fact that the plot seemed to be heading into the direction actually had a counterintuitive effect: No one wondered how he would die; we all wondered how he would get out of it, right up until the very second Nucky Thompson put a bullet in his head. Jimmy Darmody wasn't just a major character -- besides Nucky, he was the major character and to a large extent, the show revolved around him. It was hard to believe that Jimmy Darmody would be killed because it was hard to believe that the series could continue on without him (it has, and it's actually even gotten better).
Omar Little, The Wire -- I am conflicted about including Omar Little because he was a gangster who did steal from other gangsters, and it's almost more shocking that he lived as long as he did. He outlived a lot of characters on The Wire that he had no business outliving, but that's really what made his death so shocking. He was invincible. Untouchable. He was also the most beloved character in the series, so yes: Seeing him shot down, not in a gang war, but by a kid in a convenience store who shot him in the back of the head just because, well, yeah, it was a huge, out of left field shock.
Rita Morgan, Dexter -- How could we have possibly foreseen that? The Trinity Killer was dead! Dexter was happy, and heading home. The series had killed off a succession of big bads, but it had never killed off a major series characters before, and then BAM. Dexter's wife, who had nothing to do with either Dexter's job as a blood spatter analyst or as a serial killer, winds up dead, killed by the Trinity Killer before Dexter had killed him, and in such a brutal, shocking fashion.
NOBODY saw that coming (in part, because Dexter is not a sophisticated enough show to build in foreshadowing).
Teri Bauer, 24 -- The death of Teri Bauer at the end of season one of 24 was particularly shocking because it came on the heels of the shocking discovery that Nina Meyers -- Teri's killer -- was a mole, and because it came on network television, which had not -- to that point -- really committed to the ANYBODY CAN DIE trope. In fact, it predated most of the deaths on the list, so audiences had not yet gotten accustomed to seeing major characters die on cable or broadcast television so it was doubly shocking if you saw it when the season originally aired.
Nate Fisher, Six Feet Under -- Yes, he had a brain tumor, but it has been successfully removed, and Nate Fisher was the main character in a show that had never killed any of the major characters up to that point (the closest they had gotten was Nate's first wife, Lisa). It wasn't the end of the series. It was the third to the last episode in a series where every character had grown over the course of the series, and with three episodes to go, it was Nate who was the lone holdout, the guy who hadn't really been transformed (in fact, he had become less likable over the course the series). The final three episodes were supposed to be about Nate's redemption, Alan Ball was supposed to find a way to make us like him as much as we did in the first season again. But then, he had an affair with Maggie, and then NARM!
It's still the most shocking moment of television in my lifetime.
But that wasn't even the death: NO! Nate survived the brain hemorrhage, asked Brenda for a divorce, looked to be recovering, and in fact, may have found his way toward redemption by leaving his toxic relationships with Brenda. Then BOOM. Dead. How could that happen? HIS MOTHER WASN'T EVEN THERE? SHE WAS CAMPING IN THE WOODS. It was so wrong, y'all. SO WRONG. And sudden. And unexpected, and eight years later, I'm still reeling.