Neon Genesis Evangelion invokes its infamous Mind Screw in this fashion. For the first half of the show, the plot seems straightforward. Then "Adam" is introduced, and from there it keeps getting worse. Good luck if you know what the hell anyone's talking about by the last episodes.
In addition, the giant robot that blinks at you in the second episode may also be kinda confusing to most people.
Unlike some other Kudzu Plots, it's actually literally impossible to understand what's going on in the series with the information given in the actual anime series, movie included. The necessary pieces to understand the whole plot is only given in third party material, officially endorsed by Gainax.
Naoki Urasawa in general is rather a master of doing this trope right. He'll introduce dozens of often twisty and complicated plot threads throughout his manga and somehow always manages to wrap everything up in a more or less satisfactory manner by the end. It remains to be seen if his latest masterpiece, Billy Bat, certainly his most ambitious work to date in this regard, will be able to keep up this momentum or if Urasawa will finally descend, Icarus-like into the depths of a Claremont-esque morass of incomprehensibility and dangling plot threads.
Yokohama Kaidashi Kikou features a literal anti-Chekhov's Gun and introduces a number of different elements without any intention of addressing their nature. It's also an extremely powerful example of how a work of fiction can not only remain at a very high quality precisely because of it - as long as you know what you're doing.
Code Geass, much to the frustration of the fans. Three prominent examples include the nature of Suzaku's superhuman abilities (cut because it would complicate things after initial plans for the second season changed), practically anything of substance regarding the bulk of C.C.'s life before the show (considered inconsequential to the plot beyond revealing how she originally became immortal), and any additional information about Kallen's past or family besides her having a dead brother.
Or even if her brother is dead; in the audio commentary for Episode 4, the head writer teases that he might be alive, much to the surprise and confusion of Ami Koshimizu.
The second season would have originally answered that, along with introducing Kallen's father and possibly Jeremiah's sister. Oh well, What Could Have Been, I suppose...
The Big O: although the series explains quite a few things in the last few episodes, none of the fundamental reasons behind these other reasons are ever given. Such is the trouble of having the last part of a series cut out and the Myth Arc killed.
Except that Shadow Chronicles ended on a cliffhanger, like the original series, with the fate of an extremely important character hanging in the balance instead of unknown, another alien faction with very ominous intentions ready to raise some hell, and humanity and their allies really screwed at the moment. It doesn't help that this was supposed to be the beginning of a new chapter for the franchise and nothing much has happened since. And that's before taking into account the legal problems the show is having, which makes any kind of future resolution or closure to the story either very unlikely or hard without extreme Willing Suspension of Disbelief. This probably ties into The Chris Carter Effect territory as well.
There is a planned sequel, Shadow Rising; but it is postponed indefinitely due as of 2009 due to the Warner Bros Robotech live-action project. Tommy announced recently that the public should expect a 2015 release.
RahXephon suffers a wee bit from this. The nature of the Mulians, the secret conspiracy, the nature of the world, why the main character is The Chosen One and exactly what the chosen one does isn't particularly well-explained.
Yu-Gi-Oh! GX feels like this, thanks to its tendency to introduce plot points that slip into Red Herring twists: the Abandoned Dorm in season 1, the war between the Light of Destruction and the Duel Monsters in season 2, Yubel being stuck in Jaden's head in season 3, and the entire ending of season 4 all give hints of being explored and resolved at a later date, but none of them actually do. Justified for Season 4, as it was a half-season with rushed production due to the main character's voice actor having to leave the show early.
Negima! gained several levels of complexity once the Magic World arc started, and the massive Back Story started to come into play, in addition to various subplots involving the minor characters. It's generally kept under control though... until the series' finale, where most of the subplots are either left hanging or explained away in a single panel, several important questions about the main Myth Arc are never addressed, and the protagonist's main motivation gets a resolution... off-panel.
This is the primary complaint directed towards Karas. It doesn't help that a minor (but important) character speaks in un-translated Japanese subtitles.
Wandering Son introduced various plots in the span of a few chapters, and few of them get explained for a while if ever. The mangaka juggles various parallel plot points, giving each only a few panels of attention before moving to the next, leading you to reread chapters just to keep a handle on what is going on. It works somewhat better in the manga than in the anime, but only just.
Aoi Hana, by the same author as Wandering Son, is also getting there. The story is becoming a jumble of romantic entanglements, intrigues and problems with family and friends, and several plot points have already been either ignored or cut off abruptly. The author is also not above setting up important story arcs, just to halt them and concentrate on a seemingly irrelevant subplot.
Baccano! and Durarara!! both fall into this, though they tie up most of their loose ends. This is in part because their storytelling makes a mockery of chronology and in part because they are both adaptations of ongoing light novels (though the extra episodes clear up some lingering questions). Long story short, these are good examples of this trope.
Naruto has shown more and more evidence of falling into this category as the series progressed. However, the 4th Ninja War seems to be wrapping up all unresolved plot threads.
A common criticism Ookami Kakushi faces is that while the main mystery of the series is solved, several others—such as Kaori's mysterious illness or her eventual role as a White Wolf Kanon—are left to the imagination of those who did not read the VN.
Bleach: has a couple of examples of this, though with the final story arc many of the major loose ends are being tied up at a surprising pace.
The reference to Aizen having done something on a mental or emotional level to Orihime that will make her his even when she's not his physical prisoner, or the implication that she can do something to destroy the Hougyoku.
The mysterious research Szayel was engaged in that both Aizen and Mayuri seemed to find so fascinating (which included two mysterious bodies that still haven't been identified).
Why Kaoru's dislike of Ichigo culminated in a scene full of darkness and shadow where he was spying on Ichigo and Ikumi's conversation through his bedroom door. It was dropped after that in favour of the main plot and hasn't been revisited since.
Byakuya mentions that Ichigo is the second person to have seen his bankai's ultimate attack, something he only uses when he's vowed to kill someone.
It should be said that One Piece is an example, and an excellent one at that. This is partly unavoidable, as unlike some works that develop this, One Piece was intended to be long, and indeed is long. REALLY long. At over 700 chapters, it is one of the longest ongoing Mangas ever, and easily one of the the most popular being the #1 most popular in Japan, and being part of Shonen Jump's Big 3 (alongside Naruto and Bleach). This can be taken as a sign that its many criss-crossing plot threads, that can seem thoroughly tangled... are exactly what its fans ask for (or that they are perfectly OK with, and indeed, most consider it well done). A lot of this is due to the fact that if you were to read it from the very beginning, it's surprisingly easy to keep track of everything. On the flip side, miss even one chapter and you could become irrevocably lost until you read what you missed. This, and the sheer Archive Panic it can induce to get into it has turned more than a few people away from the series.
Big Finish Doctor Who: Every Big Finish plotline spawns sequels, prequels and spinoff series. Which in turn may get their own spinoff series. Standalone arcs have prose sequels, Perspective Flip special releases (which aren't available from Big Finish at all), and links to other Doctor Who media. The Doctor will merrily take a vacation in Doctor Who Magazine comics locations, meet up with Iris Wildthyme and reference future events from the new TV series — which only serve as fuel for new plotlines. Every trilogy has at least four parts, and villains or companions from the early 2000's have a tendency to return a decade later for an entirely new story. In short, every little piece of Big Finish is connected and constantly growing.
X-Men: Chris Claremont is famous in the comics community for the truly epic number of dangling plot threads amassed as a writer. Summed up hilariously in X-Men: The End, an Alternate Continuity miniseries written by (of all people) Claremont himself that attempted, in one stroke, to resolve every dangling plot thread ever introduced in the entire X-Men meta-saga (many of which Claremont had created). As one might expect, the story grows exponentially more incomprehensible with every issue, culminating with a duel between Jean Grey and Cassandra Nova for control of the Phoenix Force. Incidentally, you calculate a plot's "Claremont coefficient" by dividing the number of plot points introduced by the number of ones followed up on. If the result is over 1 in most or all episodes, you have a Kudzu Plot.
Although Claremont is deservedly notorious for this, the X-Men line's Kudzu Plot actually became far worse after he left. Notorious dropped plots include Wolverine devolving into a noseless dog creature, Cannonball being revealed as a immortal "High-Lord", and Shatterstar being a comatose boy in a mental institution the whole time (as well as his and Rictor's relationship, which was finally confirmed ten years later.) The nadir of this trend was probably the Onslaught Saga, in which dozens of hints were dropped about the villain's identity before anyone (meaning the writers) had bothered figuring out who he actually was.
Sovereign Seven: Also by Chris Claremont and was ultimately the worst offender of all. It was nothing but an interconnected web of mysteries, and was canceled after three years with not one single plot point resolved. Plus, it turned out to be the Seven were simply fanfiction written by citizens of The DCU. So it all never really happened.
Which gets really complicated since Power Girl joined the team. That entire part of her back story had to be erased (although considering the Dork Age she was in at the time, this wasn't a huge loss).
The Clone Saga: It started up as just another Spider-Man plot, but when it became the only decent comic book seller for Marvel comics during its run time in the middle of The Nineties, Marvel decided to keep it going beyond sanity. Editors and writers kept coming and going and each one had its own idea on how the plot should twist. It took about two years to kind of finish off the saga.
G.I. Joe: Larry Hama pulled off almost as much complexity as Claremont's X-Men with his run on the comic series for Marvel.
Teen Titans through most of the 90s suffered from this, with so many characters and plot threads being thrown in and focused on that it grew increasingly hard to keep track of them all.
Archie Comics' Sonic the Hedgehog: A writer named Ken Penders was attributed with starting multiple story arcs and never ever finishing them for whatever reason. This is actually a case of Mis-blamed, as most of those arcs were created by Karl Bollers when he temporarily replaced Penders as head writer. The arcs would typically go on for years with little or no development; the few that would eventually get wrapped up would finish out with the bare minimum of information, leaving an extremely large number of dangling plot threads. When Penders and Bollers left Archie Comics (Penders after 19 years of employment there), the new writer, Ian Flynn, spent almost his entire first year writing comics that tied up all the loose ends.
The early 1980s series DC Challenge was this, if not by design, then certainly by the expectations of anyone with a quarter of a brain. It was a miniseries in which the hook was that each issue was done by a different writer and artist, none of whom could use any characters on which they "normally" worked (unless they literally had to because it was set up that way by the previous issue, in which case they were supposed to shunt "their" characters off to the side as quickly as possible). Each issue was supposed to end with a cliffhanger/puzzle for the next team to solve, and it was supposed to be solvable using either clues in the story itself or well-known abilities of existing DC characters (e.g. "Superman can fly" or "Flash can run really fast"). It reached Gordian Knot status by about the third issue.
My Immortal: has the plot going from Ebony's sex life, to being tasked with killing Vampire Potter by Voldemort, to battling Voldemort, to battling ephebophiles Snap and Lupin, to sex life, sex life, sex life, to time travel and back to sex.
Stories in The Nyxverse have a tendency to start off simply, then undergo Cerebus Syndrome and become increasingly more complicated. This is especially true in the case of Nyx's Family, which was originally meant to be a oneshot but ended up over thirty chapters long, with a plot that bore no resemblance to what it started as.
Yes. Even movies can have this in special cases. For the Saw series, when the original movie ended, only a few plot threads stuck around, but nothing worth hurting over. However, once Lionsgate bought the rights to the series, Executive Meddling hit hard and forced the writers to make an endless string of subplots and character histories to interconnect with the overall storyline, mainly to create one Sequel Hook after another (to make sense of the ensuing chaos, no matter how increasingly illogical it got). Saw 2 pulled this off very well and 3 was somewhat cohesive too, but after that, the writers got crazy. Saw 4 was almost LOST-like with its Mind Screw chronology and how it complements Saw 3, and Saw 5 was an Whole Episode Flashback that went back as far as scenes from Saw 2 to explain how one character was involved. At least Saw 6 neatly wrapped up most of the previous subplots from 4 and 5, but only time will tell if the next film ends the remaining string of plots with grace.
In regards to Saw 7... YES.
The Room is extremely guilty of this. There are several subplots thrown in, but none of them are ever resolved. Examples include Lisa's mother offhandedly mentioning she has breast cancer, a character's drug-related debt which ends in a violent confrontation on a rooftop, and, in the most infamous scene, all of the male characters playing football in tuxedos. None of these subplots are ever mentioned again nor are they given any sort of closure or impact the plot in any way.
Played for Laughs in Aqua Teen Hunger Force Colon Movie Film For Theatres - during the second half of the movie, particularly during the last 10 minutes, a pile-up of revelations concerning the characters' origins occurs to the point where the only one left remotely excited about anything in the end is Meatwad. To clarify, it's revealed (or claimed) that:
Dr Weird invented the Insaneoflex to build up someone's muscles, so he could steal them and use them to fight Frylock.
Frylock created Dr Weird, despite thinking vice versa.
Dr Weird created the rest of the Aqua Teens.
Frylock is implied to be a lesbian trapped in a man's body, trapped in the body of a talking box of fries/VCR. (Although this is subtly hinted at throughout the series, making this twist a Rewatch Bonus).
The mooninites created Frylock, or rather claim to.
Everyone was the offspring of a talking slice of Watermelon living with Neil Peart called Walter Melon.
The mother of the Aqua Teens was a talking burrito that shows up out of nowhere. This is the twist where almost everyone stops caring.
The Dark Tower suffers badly from this. In telling Roland's history, a good four hundred something pages is dedicated to a love interest of Roland's and how it helped start what is undoubtedly the most catastrophic war in the history of everything, yet only one chapter is devoted to its final battle, one sentence describes how it ended, and one sentence describes how Roland survives. Roland's parents only make one or two appearances, John Farson never shows up, and the fates of Alain and Cuthbert are practically Hand Waved. In the main plot, Continuity Drift is blatant, anticlimaxes are everywhere, and there are so many flimsy explanations and Plot Holes.
Stephen King stated in a recent interview that he would be writing another Dark Tower novel, which would take place between books 4 (Wizard and Glass) and 5 (Wolves of the Calla). It is reasonable to assume he will be expounding on the aforementioned plot holes and dangling storylines.
To be fair, WAY back when the Dark Tower was first released, King said that he intended to write a decalogy. Somewhere along the line he lost three books; which left a lot of early plot hanging.
The comic book adaptation starts as an adaptation of the main flashback of Wizard and Glass, then continues to cover Roland's life up through and beyond the Battle of Jericho Hill.
The Hyperion Cantos turns into this at the end of the first book. It starts off strange when the nature of the Time Tombs are explored in greater detail. It gets a bit weird when it introduces the Technocore, the way it functions, and its ambitions. It goes right off the deep end when every single plot element from the entire book is linked together in a matter of ten pages. Have fun with the next one.
The Wheel of Time, with the side effect of grinding the later books to a halt as the same (admittedly huge) amount of book is split across a massively increased number of plot threads. The 12th and final book was supposed to tie off many of the loose ends, but then the author died.
The last book is being finished by another author though. So we might actually see those ends tied up after all. In the attempt to do so the final book's word estimate now stands at around 800,000, around 2 times or more than the already Door Stopper series is used to, leading to the publishers splitting it into 3 books.
It is worth noting that Robert Jordan actually didn't want to resolve all of the plotlines by the end of the story, as that would make it feel too much like a self-contained world that ends with the last book, whereas he wanted it to feel like the story never really ends, only the books do. He was quite clear that he wanted some plotlines left dangling at the end, not as hooks for sequels, but for realism purposes.
A Series of Unfortunate Events has a fairly large Kudzu Plot in the later books (the Ancient Conspiracy that was abruptly introduced after Book 5 remains fairly inscrutable), although the Lemony Narrator explicitly tells us that some mysteries can never be solved. The End made good on this, so to speak, by pointedly not answering almost everything.
Roger Zelazny's The Chronicles of Amber series. The first five volumes tell a reasonably self-contained story that ties off tolerably well. The second five introduce enough new characters to double the size of the cast, retcon numerous elements of the first series, and more runs out of steam than actually ends. (That is then followed up by some short stories that mostly serve to complicate things further.) Apparently Zelazny planned to write another five volumes, but died before he had a chance to tie everything up, though.
The New Jedi Order had Han and Leia's son Jacen as a God-Mode Sue, Centerpoint Station (a space station in the Corellian system) able to destroy stars, and Han's cousin Thrackan out of prison. Oh, did I mention Luke no longer believes in The Dark Side because a Jedi from the old Order told him it didn't exist? Jacen doesn't either, and he's adopting a "broader" view of the Force. (All of this is resolved in Legacy of the Force, along with a few attempts to fake Chekhov's Gun. Jacen's a Sith, Luke realizes The Dark Side is real, and Han joins up with the Fetts to take down his cousin.
The Maximum Ride series suffers heavily from this, especially in the later books. Pretty close to everything in the entire series is still unresolved, and each book creates more mysteries at a furious pace. It would be a lot easier to list what actually has been resolved, or at least handwaved.
Several Warrior Cats books work this way. The second series makes you wonder who was working with Hawkfrost, and what exactly was going on with Brook and Stormfur coming back to the Clans, and the state of Squirrelflight and Brambleclaw's relationship, as well as a few minor things. The third series was worst about this: they still don't know why they have the prophecy, it wasn't clear where Sol went, we don't know what exactly Tigerstar was up to, and we've just learned that Hollyleaf isn't the Third after all. We didn't even know if Leafpool had stayed with the Clan because the authors forgot to mention her again for the several chapters after she leaves her den. The fourth series wraps things up a bit better, but still left a couple things open because the authors thought it would break the mood to say "so-and-so chose this cat as her mate" after the battle of battles.
The first Dexter novel never really explains how Dexter had "visions" that told him about the murders. The murderer turns out to be his brother, and their shared experience in the shipping container could explain why he was compelled to look there (albeit in a loose and sloppy way), but how on earth did he know to randomly go outside in the middle of the night, just in time for the murderer to throw a head at him?
Harry Stephen Keeler's "webwork plots" are built on this, consisting of different threads(characters or objects) engaging in complex interaction with several other strands until a reveal clarifies it all. Like the pure plotiness of The Man With The Magic Eardrums.
The Neverending Story has some loose threads deliberately in it ("But this is another story and shall be told another time.") And at the end of the book the snakes won't let Bastian return to the real world because of the many unfinished plots he left behind. Bastian protests that every story necessarily has SOME loose ends, even if very minor, and could be expanded upon indefinitely, so he would never be done with it. Atreju volunteers to take care of it.
Torchwood has a massive Kudzu Plot at present. It constantly raises new questions about Captain Jack's origins and past (or should that be future... Time Travel is confusing stuff, especially in the Timey-Wimey Ball that is the Whoniverse...) not to mention all the minor unfollowed plot threads brought up throughout the show. What the flip is Jack's birth name anyway? What the hell were those things that took Jack's brother Gray? What is the mysterious "Storm" that the former leader of Torchwood 3 was talking about after he murdered the staff and killed himself? Is it something that already happened or something that's going to happen? Who is that creepy, seemingly immortal tarot card reading girl and when is she going to call in the favour Jack owes her? What the hell was Billis Manger? When will Cell 114 strike?
Of course, this is really a carryover trait from Doctor Who. There it took until season six to even learn the name of the Doctor's race. Some of the dangling plot threads that are still left from the old series include the "Doctor is Merlin" thread, the war of the Great Vampires and the Time Lords, and what, exactly, happens in the 51st century. What the flip is the Doctor's birth name anyway?
Not to mention the seemingly abandoned Cartmel Masterplan (though it, like various other plot threads and references, has been followed up in the Expanded Universe).
In "Doctor Who" "Journey's End" a lot was tied up. However RTD and many fans seem to have been so caught up in Rose returning from a Parallel World that a lot about her return isn't explained. There is the claim she was using a Dimension Cannon and the Hand Wave that she appeared in an alternate timeline and knew so much due to her world being slightly ahead. However a lot of her role in "Turn Left" is left unexplained, along with how she was able to appear on the TARDIS scanner, or a screen on the planet "Midnight" centuries into the future. It doesn't look like those will ever be explained.
Series 5 leaves several major unanswered questions. What is the Silence? Who or what was the mysterious force that took control of the TARDIS in "The Pandorica Opens", and how did they do it (and where did that creepy voice come from)? And why would blowing up the TARDIS cause the destruction of the universe (which even the Doctor says is a good question)? Not to mention all the questions surrounding River Song...
Series 6 answers the first of the above questions, but leaves the others hanging and raises several more: If blowing up the TARDIS was the Silence's plan, did they actually intend to destroy the universe? If so, why? Why must the Question never be answered? Et cetera... At least most of the major questions about River were answered.
The Series 7 Christmas Special works to answer quite a few threads as a way to wrap up both Matt Smith's tenure as well as the original limit of 12 regenerations. Unfortunately they managed to disappoint many fans with some of the revelations (The Silence, Trenzalore , The Doctors Name).
The huge amount of this in Doctor Who over its run was spoofed in the Mark Gatiss comedy sketch "The Pitch of Fear", which imagined someone trying to pitch the show to a BBC executive. The absurdity is that he's planned out everything, including obvious Writing by the Seat of Your Pants moments - for instance, he tells the executive that he's planned out that the first four Doctors will be a "crotchety old man", a "cosmic hobo", a "dashing dandy", and someone with "a mane of hair and a curious old-young face", that Jon Pertwee becomes available to play the Doctor in 1970 but they'll have to get rid of him before he's due to be Worzel Gummidge, and that it's important to get the costume designs of the first four exactly right but after that "anything goes... jumpers, cricket whites, a clown's costume...", so long as, to preserve the mystery of the character, they have red question marks put on them.
Mr Borusa: How long do you envisage the show running?
Since it was both Screwed by the Network and Cut Short, most dangling plot threads in American Gothic are of the 'and the cycle goes on' variety, where we never know in the end whether Buck will ever be stopped, whether Caleb will go evil, whose side Selena is really on, and so forth. But there a few genuine moments where an element was introduced, then never revisited again, leaving for some major head-scratchings. Examples: Was Sutpen of "Damned If You Don't" really a ghost/spiritual summoning of Buck's, or not? Did Buck drive his girlfriend to suicide, or not? Whatever happened to the fellow Merlyn was romancing when she came back to life? Will Dr. Matt ever get free of the sanitarium? Whatever happened to Selena's father, and will he and she ever reconcile? (This last one is particularly distressing since, thanks to the episode in question never being aired, very few people even know it exists.)
Back to the 60s: Coronet Blue. To wit: guy found with no memory except for the titular Arc Words, which never ended up resolving to anything since the show only ran a single season.
The short-lived series John Doe headed into this territory as well.
Cut Short after the first season, this show left off its Kudzu Plots before it even had much chance to even try to explain them...
Soap suffered from this, notably though it had a whole complex plot after the first episode. Creator Susan Harris had written the show as a five-season story arc before it began. When ABC opted to cancel the show after four seasons, however, it ended on an episode full of cliffhangers, with several main characters facing seemingly imminent death and several plot threads left hanging.
The show's spin-off, Benson, did at least somewhat clarify Jessica's fate.
Stargate SG-1 suffers from this as well. What ever happened to that hastily-put-together human kid "Charlie" from the Re'tu episode? Everyone's just assuming that the Tollan were wiped out by Tanith's forces (despite it being highly improbable that a single Goa'uld mothership, no matter how advanced, would be able to prevent everyone on a spacefaring planet from escaping), but they never went back and conclusively proved it. Did Colonel Landry and his daughter Dr. Lam ever put their differences aside? Is freaking Athena still free on Earth and running a company? Whatever happened to Daniel's grandfather? Are there actually fish in Jack's pond? Did Jack ever get a dog? And what exactly is a Furling anyway?
And of course how long are they going to be able to keep the Stargate program a secret with the hundreds of service members who spend years offworld.
Also the Meaning of Life Stuff from the first season episode "The Torment of Tauntalus" is probably the biggest unfired Chekhov's Gun in the series's arsenal. It's a book written by the Four Races, written in a universal language that was DESIGNED to be easily decoded. It's briefly mentioned in the second season, but never again. This would be like an alien species finding the golden record in one of the Voyager probes and never figuring out how to listen to it, in spite of the obvious pictorial instructions on its jacket.
Also there are some suggestions that Babylon was protected from the Goa'uld by an alien race. The alien in the first season episode "Fire and Water" asks the team if they're from the same planet as Babylon. Also the first appearance of the four-part super-weapon that Anubis puts together at the end of the sixth season is The Eye of Tiamat; Tiamat was actually the villain of Babylonian mythology, suggesting that Marduk and the other gods were aliens who fought the Goa'Uld. Again, this was never brought up again.
The people behind the new Battlestar Galactica were always fairly open that 75% of the show was being made up as they went along, leading to a fair amount of Kudzu by the end. The writers made a valiant attempt to wrap everything up, but plenty of mysteries were just dealt with by using a blatant Info Dump and a Hand Wave saying it was God's will.
Heroes, anyone? People and whole worldlines are MIA. And now that it's been cancelled, they're likely to stay that way.
The X-Files ended never having cleared up half of what was going on.
The 4400 did this. Probably intentional, as with an ensemble cast you never know which plot hooks you'll have the opportunity to follow up next. Did get pretty annoying, though, when the biggest teaser at the end of season 2 didn't show up till halfway through season 3.
Supernatural unfortunately ended up with a Kudzu Plot, likely a result of minimal planning and continuity changes over time. Unanswered questions include whether or not Sam really was corrupted when brought back to life as Azazel said and why all of Mary's friends and acquaintances were killed off, which wasn't justified by her eventual backstory.
Should be noted that some of this is intentional; the writers and producers want to leave some mysteries even after the show ends.
Merlin is headed this way, though only time will tell if the writers can resolve everything they've raised thus far. This is especially true of the complex but still murky Back Story of Camelot's first generation, namely what the heck went down between Uther, Igraine, Nimueh, and Gaius when Arthur was conceived. Apparently Uther approached Nimueh (brought to the court by Gaius) to cast a spell to help his wife Igraine conceive, resulting in her death, Nimueh's banishment, and Uther's crusade against magical creatures. Every character who lived through those events tells a slightly different version of what really happened, but whether this is a variation of The Rashomon, or whether there's something more that the writers haven't told us yet, remains to be seen.
There are also plenty of unanswered questions about the Druids (especially Mordred) and how much they know about Merlin (who they call "Emrys") and what they expect from his destiny.
Babylon 5 was tightly plotted from the beginning and manages to maintain a tight story throughout. Unfortunately, numerous plot threads from early in the series had to be quietly dropped when the plot had to be modified to account for cast changes. Among the casualties: The data recording Kosh made of Talia Winter's fears, Captain Sheridan's knowledge of secret societies & black projects and Catherine Sakai's growing involvement with shady mega-corp exploitation of dead worlds - although the last one was resolved in one of the tie-in novels.
The ill-fated TV adaptation of Animorphs was forced to condense an entire season's worth of plots into a 90-minute three-part episode. The result, while superior to anything else the second season produced, is deeply confusing and disjointed, and the episode (and series) ends with many of these plots still unresolved.
Season 2 of Revenge quickly devolved into an incomprehensible mess involving a Nebulous Evil Organization whose ultimate goals were never clear, nor exactly how much or little they were involved in the various plot points going on. Notably, this actually led to the show's creator being fired, and season 3 starts with a mass burning of the whole thing, abruptly revealing that the entire group had been arrested between seasons.
The Whateley Universe, since the storyline (about a hundred short stories and novels to date) has only really covered the first term of school. Although they did eventually explain what really happened to Cavalier and Skybolt.
This is as early as episode five and snowballs from there.
The Salvation War has at least half a dozen subplots going on at any one time, so that some story threads just peter out after seeming like they would be much more important. Particularly obvious is the resistance movement in Hell of dead ancient Romans; the author admitted soon afterward that he'd planned far more for them but didn't have any room for it. A big part of the problem was that The Salvation War contained contributions from a number of authors and integrating these contributions presented a major editing problem. A major weeding exercise was in progress when the project shut down.
Marble Hornets is pretty much built on this trope. Actual answers are few and far between anyway, but any time one is actually given, it's guaranteed to be accompanied by a half-dozen new questions.
Marble Hornets' "heir" (as some call it) Everyman HYBRID has been accused of this, plus the fact it's spread over many websites (more than Marble Hornets). This has led to a Broken Base among the fandom.
While not too complex, all the plot threads in the BIONICLE serials are definitely difficult to keep track of. During the course of the '08, '09 and '10 stories, they "advanced" as the following:
War raged. The forces of good allied themselves with the evil Barraki (except for a rogue member) and Dark Hunters, but they had their own agendas: the Barraki re-formed their armies to take over the universe, while the leader of the Hunters discovered some strange viruses and formed a plan to, yes, take over the universe too, but not before killing his only friend, making his big reveal as a double agent completely pointless.
Meanwhile, the leader of the good guys, Toa Helryx, trapped inside the head of the main villain (who himself was the universe at the time), decided to kill everyone, but suddenly a mass of random characters appeared (one of whom was dead-but-not-really and also wanted to take over the universe), but they got launched into space, then teleported to a place where they met their potential creator, a Great Being.
Toa Lewa, after a series of body-swapping, got lost in the jungle, where a tribe of natives captured him. note By this time in the main story, the villain has already been killed and the universe destroyed, so there go all the villain plots... Toa Kopaka wanted to find Lewa, but after discovering that the Toa Mahri had been enslaved by a godly mutant, found himself in a completely unrelated detective story with Toa Pohatu, and then, space travel.
Another group of heroes has also been dispatched to locate the Great Beings, but fell victim to a different tribe of jungle-dwellers.
Unrelated to all these events, Sahmad set out to find the one who killed his tribe, stumbled upon an age-old, dream-sucking shining ball of tentacles, after which his story finally got connected to the plot about the enslaving mutant. So far, Sahmad's is the only story to have been wrapped up.
There is also Marendar, an artificial assassin, designed to kill all good guys, whose story didn't last beyond his introduction, thanks to all the other plots.
Oh yeah, and Voporak stole the legendary Mask of Time to deliver it to the Shadowed One who formed a new evil allegiance with random villains. And this, people, is how the story was when Lego definitely stopped to post updates. Yes, all the above lines are how Bionicleended.
2005 offered an earlier example. Keeping track of the stories detailed in the novels, comics, DVD movie and on-line clips was next to impossible, as most of them occupied the same timeframe instead of following each other in a linear fashion. Said movie was also an interquel to the previous one, and the comics contained a confusing bit of Flashback Within a Flashbackwithin a flashback amongst a sea of pointless Filler.
The Metal Gear games are very well known for this. In the end though, they manage to tie everything up pretty well after numerous retcons and mind screwdrivers, but even then one or two holes are left open.
The original Metal Gear Solid had a tight script while subtly leaving a door open for sequels. The following title, Metal Gear Solid 2: Sons of Liberty, EXPLODED with triple-crosses, Xanatos Gambits, fevered conspiracy theories, and individual cliffhangers for every character still left alive. The long-awaited Metal Gear Solid 3: Snake Eater (released three years later) flashed back to the 1960s to expose the origins of this conspiracy, but wound up being (mostly) self-contained, leaving Metal Gear Solid 4 the dubious honor of explaining all these plot entanglements and twists with over 9 hours of cutscenes.
As far as we know, the story is still not completed, with more prequels on the way.
The Kudzu plant is actually referenced in Metal Gear Solid 3 amusingly enough. It is noted how invasive the plant is and that it quickly kills other plants nearby because of how fast it grows. This entire franchise can be likened onto the plant.
The Legend of Zelda obviously had its plot made up as the series went along. First, it was the original, a sequel, and a prequel. Then it was a prequel to the prequel and sequel to the prequel. Then came a sequel in an alternate timeline to the prequel and another sequel to the prequel and a side-series and kind of tied in to the original prequel and a pair of games sort of sitting around with nothing to do with the others. Fans will debate endlessly exactly what order the Non-Linear Sequels are supposed to go in. Most fan-constructed timelines will resemble family trees more than linear timelines.
Legacy of Kain: A vampire lord is trying to save the world by restoring the destiny of himself and his son to their rightful paths. It's pretty simple until you add in all the false gods, time travel, multiple paradoxes, fate/destiny vs. free will, Amnesiac Dissonance, resurrections, all the characters having secret motivations and trying to manipulate everyone else while simultaneously being manipulated themselves, and on and on and on. Basically it's the king of Gambit Pileup.
The Kingdom Hearts series has slowly become infamous for this. For new people, the original Kingdom Hearts had a very clear plot: monsters that come from the darkness of people's hearts who are battled by the current wielder of a giant key that cuts hearts, as he looks for his friends whom he lost. A bit weird, but clear. Then Organization XIII came in, a new enemy that raises some questions. These are answered in KHII... by raising more questions. Many more. It all kept snowballing from there.
A lot of this has to do with Nomura's philosophy of adding plot twists, no matter what the rhyme or reason, in order to keep things "surprising." When asked what the most important thing to him is when making a story, he replied with this:
Nomura: Making it "surprising." While I'm writing out the plot, if things seem that you can predict the outcome on your own, then I think of a different, unexpected development.
The prequel game Birth by Sleep was an extended Mind Screwdriver that explained the origins of the Big Bad and Castle Oblivion and added backstory about a few characters. Then 3D came along and added Xehanort time-traveling to set up his own rise to villainy, and Nobodies manifesting hearts through friendship, and other such plot elements in addition to cranking the Mind ScrewUp to Eleven. At this point, there are so many connections in the plots of the games that 3D needed a Memento feature to prevent Continuity Lockout.
Dissidia: Final Fantasy had shades of this, with some vague terms and references that didn't add up, but the Kudzu Plot really got going with the prequel, Dissidia 012, which was filled with retcons, twists, clones, alternate universes, and new questions left unresolved and hanging all other the place.
Marathon. You have implications that the precursors were at Tau Ceti. Then there are hints that the main character is a Jjaro. Hints that he is a battleroid, Beowulf/Roland/everybody else, and the protagonist of Pathways into Darkness.... all at the same time! Oh, then Durandal likes to speak about philosophy. This is before the third game turned into a Cosmic Horror Story that abused the multiverse and Timey-Wimey Ball to no end. By the time WMG attempts to mesh the timeline in with the Haloverse come along, it almost sounds normal. Almost.
Oni wound up with a Kudzu plot when Bungie rushed its release to prevent it from falling into Development Hell before their merger with Microsoft. The main plot is wrapped up by the end, but there is so much story and information that was left on the cutting room floor...
Chrono Cross... The best summation is probably "Wait...? What...? Didn't he just...?"
It really is stunning how Masato Kato took a plucky, fourth-generation console game about saving the world from space termites and turned it into... well, Immanuel Kant set to music and psychedelics.
One of the biggest problems is there are now at least 6 different versions of what happened at Nibelheim. Granted there was about 3 in the original version as it is, but now it's become the video game version of Rashomon.
One of the executives at work in Square Enix has now decreed that each version is seen from the perspective of a different character. So now it is OFFICIALLY the video game version of Rashomon. God damn it Square Enix...
This is one of the most defining aspects Dark Souls's story. There are so many aspects of the lore, characters, character motivations that are left up in the air including what effect the end of your journey has on the world.
Max Payne and its first sequel gave us Address Unknown, a TV show from the 90s that was canceled after six episodes, but developed a cult following. There's more than a little Twin Peaks about it.
The final arcs of It's Walky! seem almost unfollowable. There were government conspiracies and evil aliens, and other, eviller aliens that battled the first aliens, and a mystery character that was one or more of an alien, a robot from the dawn of time, the protagonist or a tertiary character from three years ago. There was at least one invasion of the Earth, and characters dying and other characters trying to bring them back to life, and ooooh, something about Illuminati from another universe and clones and hybrids and ow my brains. All this from a comic that started out as college-based gag strip. Perhaps it was best that the story ended then, before it took a team of Talmudic scholars just to follow the updates.
Don't forget the talking car and the zombie hordes, which weren't so much Kudzu Plot as they were practically random elements that cropped up at the last minute. Fortunately they canceled each other out.
To make it even worse, as soon as the strip ended, David Willis started doing Joyce and Walky, featuring a number of characters from the earlier strip, except all of the weird alien invasion plot threads were utterly stopped and it became a cute little domestic comedy strip about a young married couple. A formerly superpowered, alien-fighting couple. Which was never mentioned again.
This was followed by Shortpacked!, in which many of the rest of the characters started working at a toy store, with only occasional nods to the past.
At this point, it would take a chainsaw to prune the plot of El Goonish Shive into something sensible. And even when some of the threads are about to be tied up, Dan Shive takes another swig of The Chris Carter Effect and makes it worse.
Perhaps the biggest offender is Lord Tedd, an alternate dimension version of Tedd who was built up to be a major player early on in the plot, but after only 2 or 3 appearances has yet to appear or have any apparent effect on the plot outside of one of his underlings showing up during the Painted Black arc to give Opposite-Sex Clone Ellen her own childhood memories apart from Elliot. Only recently has he even been alluded to again, with Tedd having built a Magitek gauntlet similar in appearance to Lord Tedd's gauntlet which, just like Lord Tedd's first appearance, give him Black Eyes of Evil when he uses it. Dan Shive eventually expressed regret that he introduced the character as early as he did.
Sluggy Freelance. For those who want a little context but don't wish to engage in an Archive Trawl, Here are some of the things waiting to be resolved: the origin and nature of a re-incarnating knife-throwing acrobatic assassin with wild red hair who alternates between normal and insane with every incarnation, the origin and intentions of a talking sword fueled by innocent blood, the last names of all of the characters save one, the intentions and plans of at least one and possibly more vampire clans, the actions of at least two separate cults of demons bent on causing the end of the world, the fate of the original world-ending demon that those cults worship, the intentions and fate of the obligatory shadowy corporate conspiracy, the fate of a character who was seemingly Put on a Bus but who is continually referenced, the plans of the inhabitants of the dimension of pain who have recently acquired a new leader who goes by the name Psykosis, the origins and intentions of a certain switchblade wielding, superstrong mini-lop rabbit with a bad attitude, and the fate of the inhabitants of a dimension stuck out of time. This is by no means a complete list.
Don't forget how many of these plot points were abruptly dropped. Most glaring was the outside time arc, which just gets dropped at a relatively major event with maybe 5% of its story left to be told. A large number of fans of the comic hated the arc because, except for Bun-Bun (who got his exit some time before the end), there were absolutely none of the standard cast members in the arc. The reactions on the forums were overflowing with vitriol and they wanted Pete to get on with other unresolved plotlines, so he made attempts to cut it short before just dropping it altogether.
Want to know the real irony? Abrams has said that he hated how Chris Carter had clearly been making up the plot of The X-Files as he went along.
This has actually become a potentially apocalyptic problem in-universe. The Web of Fate is so tangled at this point from plot kudzu that the Spider maintaining said Web had a nervous breakdown and if the Web isn't untangled soon, it'll break, destroying the world.
David Gontermanloves this trope to pieces. Almost all of his stories will set up plot points just to abruptly cut them off, refer to past events that never happened on screen, and otherwise just pad the story without giving satisfactory explanations or conclusions. This becomes a problem when these extraneous plot elements start conflicting with each other (for example, he might set up a Masquerade in the first couple chapters of a story, then just throw it away in order to start having plots about other members of the so-called "masquerade"). It's rather impressive that within the span of 240 strips over about two years, the original FoxFire probably has more dangling plot threads than Sluggy Freelance has in its eleven year daily tenor.
Captain SNES started in 2001. This strip is from 2003. The sprawl has increased since then. Uniquely, there are actual in-story reasons for the sprawling plot; the entire story is a flashback being narrated by the protagonist to a mysterious captor who wants to know, and, in order to spite said captor, the protagonist is being as obtuse, misleading, and meandering in the telling as he possibly can.
MegaTokyo. Ever since one of the creators left, the comic (and its update schedule) has slowed down and sprawled sideways. This carried on for so long that people were honestly shocked when the latest chapter suddenly revisited the zombie invasion and began to drop enormous clues as to the true nature and powers of Epileptic Tree-bait Miho.
Gunnerkrigg Court: Every answer we get just seems to raise more questions. However, Tom Siddell assures the fans that he doesn't introduce any mysteries without already knowing their resolution; barring a premature ending, everything will be explained.
This has been heavily lampshaded in The Rant—see the page quote. Or for example a strip featuring a never previously named character inexplicably walking through a glowing triangular portal to a "lesson" with the "old man" had the comment "Mystery solved." It was not.
Less than a day after that page went up, someone on the official forum guessed, based on a detail from that page, that said girl was the Valkyrie Brynhildr.Word of Tom immediately confirmed that this was correct. So the mystery really was solved.
The amazing thing about this is that the author, in a blog interview, explained that he has a terrible memory for many things, but every facet and detail of Homestuck is vivid and clear in his mind. Reportedly, he wrote the 4/15 recap purely from memory.
Homestuck's nature as this is probably best described in this quote from Hussie's tumblr:
"The thing is, Homestuck is both a story and a puzzle, by design and by definition. If asked to define it, “a story that’s also a puzzle” is as close to true as any answer I’d give."
Scary Go Round, surprising for a comic without many vast mysterious conspiracies, left plot threads hanging all over the place. In one case, a villain's comeback was left hanging for so long- must have been years- that she was physically almost unrecognizable when she finally reappeared, because the comics art style had changed so much in the meantime.
Sonichu suffers from this horribly. A lot of the Kudzu Plot problems lay in creator Christian Weston Chandler, mostly due to the fact that he keeps shifting plots around to suit his needs (from attempting to woo video game companies to attempting to woo potential love interests to just getting rid of detractors.) Each shift would leave more questions than answers, leading to Issue 10, where he'd plow through those loose ends with a machete, leaving the reader feeling very empty. Even then many plot points are just never brought up again. Metal Sonichu being stuck on the moon yet still alive really seemed to setting up something later down the line, but the whole thing is just never mentioned again.
Concession was ended because of this. The plot just went completely out of hand and nothing made sense anymore.
1/0 thrived on this. Rather impressively, most of it did eventually get resolved.
Shadow of Israphel is looking this way. We still have no idea who Israphel is, except that he's apparently Reverend_John's son, who's supposed to have been dead for 5 years, and yet has been haunting Old_Peculiar for much longer than that. Oh, and he has 2 graves. The greatest threat to the world is SAND. Except that the Sand is actually a prison for an army of giant evil robots. What? And we still have no idea what the facilities in the Nether are, who N-Comm Systems are and how they are from the future, what the Sentinels actually are, what the Turtle God was, how Shiplord_Hubert ended up in the Desert, who the Templar Kings are, and a whole lot more. We may never know.
Transformers Animated delved into this in its third season. Presumably, the planned fourth season would have tied up somewhere between most and all of the loose ends, but the show got canceled before that could happen, meaning the third season finishes out with many plot points unresolved, including but not limited to: Since Word of God states that Blurr actually survived being compacted by Shockwave, what would have happened to him? What happened to the Predacons after they woke up on the island and found themselves surrounded by Maximal-esque animals, and what were Waspinator's "plans"? What ultimately happened to Ultra Magnus? Whatever happened to the Constructicons besides Scrapper? What exactly happened to the Earthbound Autobots after they returned victorious to Cybertron? How did the protoform Sari was made from get to Earth? Designs from the fourth season have been released in part via the Allspark Almanac and via conventions that partially answer at least some of these: Blackarachnia would have been making an army of Predacons like Waspinator, Ultra Magnus would have died, the Constructicons all survived the explosion on Dinobot island, regrouped, and Dirt Boss has them working on building Devastator, and while Sari and Bulkhead would have stayed on Cybertron, the rest of the main cast would have traveled back to Earth to hunt for Energon with Jazz and Ironhide joining them.
The Avengers: Earth's Mightiest Heroes rarely has an arc that doesn't branch off into at least two more by the time it finishes. Probably the most important example involves Loki's invasion of Asgard early in season one. After Thor thwarts the invasion, Loki gets banished, then breaks 74 Midgardian villains from their prisons to distract Thor from interfering with another takeover attempt. The sudden increase in crime rate leads Thor to join a newly founded superhero team, the Avengers. Several of the criminals that escaped proceed to carry out their own plans for taking over the world, which the Avengers must stop in addition to saving the Nine Realms from Loki. Let's not get started on how many of those other villains' schemes open new cans of worms.