[[WMG: Marv is drunk or on drugs in the second film]]
* It would explain why he seems so much dumber and goofier than in the first film.
* Perhaps the head injuries he sustained in film one have played havoc on him?

[[WMG: Home Alone 4 is a dream of Kevin's as an adult]]
* This would explain continuity descrepancies and the appearance of technology not around in 91 or 92.

[[WMG: Kevin, his family, and Harry and Marv all get killed in the second film and the final twenty minutes or so of the movie takes place in the afterlife ]]
* Marv dies when he gets electrocuted, Harry when he sticks his flaming head in the kerosene-filled toilet, and Kevin himself dies either in the ensuing fire or from some other mishap (such as possibly falling into one of his own traps). Kevin, Harry and Marv wind up in Purgatory where the next segment of the film takes place, and when the pigeon lady shows up to rescue Kevin from Harry and Marv, she is actually an angel sent by God from Heaven to save Kevin; the cops who arrest Harry and Marv are Satan's minions coming to take them to Hell. Kevin's mom dies when she is murdered by a random thug on the streets of New York (especially considering it was the early 90s, back when crime was still rampant in New York City), and joins Kevin in Purgatory, and the rest of Kevin's family are killed in a plane crash while transporting their bodies back to Chicago. The last scenes of the movie take place in Heaven where Kevin's family are reunited with him and the mom--note the cheery mood and how brightly lit the "hotel suite" is.

[[WMG: Kevin grows up to be [[Franchise/{{Saw}} Jigsaw]] ]]
* Kevin was quite adept at dishing out vigilante justice with a variety of gruesome traps, particularly for an 8-year-old. It takes a twisted mind to permanently brand someone with a doorknob. His neglectful parents apparently never bothered getting Kevin therapy after two felons threatened to torture and murder him, since he deliberately runs away from a second family vacation, and his traps are noticeably more brutal in New York. Imagine what a kid like that would grow up to be.
** As a preteen, he was like [[Film/TheGoodSon Henry Evans]].
** Chris Columbus in the commentary did say that he once pitched an idea where a grown-up Kevin escapes from prison. You might be on to something.
*** So Kevin grows up, gets sent to prison for something (most likely a trap or prank gone horribly wrong), escapes during a prison riot (which he himself caused), flees the state, hides away until the heat is off, and legally has his name changed to John Kramer. It's all falling into place!
*** Or he was placed in witness protection and his name is changed to John Kramer. Coming so close to losing his life at the hands of the wet bandits made him deeply appreciate his life, and because his TrapMaster abilities were what saved him, he eventually puts two and two together and becomes Jigsaw.

[[WMG: Kate had an affair with Gus Polinski ]]
Even though we don't see them snog it could be implied Kate and Gus at some point between the airport at Scranton and Kevin's home had an affair. A clear sign of Kate falling in love at first sight with Gus is at the airport in Scranton where she smiles awkwardly at him after he introduces himself and still has that lovey dovey look in her face in the lorry. It is possible Kate does not have a spark in her marriage with Peter anymore and found Gus more her taste than her husband. Of course Kate and Gus would keep this affair a secret so Peter would obviously never find this out.

[[WMG: Fuller is actually Kevin's half brother ]]
We know that in the film the guy who plays Fuller is Malculary Culkin's brother in real life but Fuller is actually Kevin's brother not his cousin or at least half brother. Even though Frank appears to be the dad Peter is ACTUALLY the dad. For one thing Fuller looks like Kevin in the face including the eyes, hair colour and lips. And let's not forget Kevin and Lennie one of his sisters have blonde hair. So by putting two and two together Peter before the arrival of Fuller had an affair with Leslie and accidentally got her pregnant. But it is possible Leslie still had sex with Frank afterwards and missed her period making her think Frank is the dad. So if that the case Peter does not know Fuller is his biological son instead of being his nephew.

[[WMG: Kevin grows up to be Film/TheCollector, is more like it.]]
Because he does [[BoobyTrap booby traps]], not [[DeathTrap death traps]]. And the premise of The Collector is basically an R-rated Home Alone. Maybe grown up Kevin doesn't care about justice anymore; instead he's simply a {{sadist}}, and the ComedicSociopathy has turned into TorturePorn.

[[WMG: More cheerfully, Kevin grows up to be a brilliant engineer/mechanic/architect/etc. Perhaps he is already a child prodigy in one or more of those fields.]]
Actually building those traps (rather than just thinking them up) is quite beyond the skill of most children, as Roger Ebert pointed out. Particularly the ones in the second movie.

[[WMG: Even less cheerfully, Kevin grows up to be [[Film/TheDarkKnight the Joker]].]]
He has already shown a disregard for the law and a preference for chaotic, convoluted plans over straightforward ones, not to mention causing much more pain than is strictly necessary to accomplish his ends. He is adept at forcing his opposition to second, or even third-guess their own decisions. Several of his traps can only realistically work if he is either a genius at reworking his plans on the fly or he has eight or nine layers of backup plan to fall back on.
* The progression of events is likely similar to the "Jigsaw" theory above. A prank or trap goes wrong and someone is killed or seriously hurt, Kevin goes away for a long stretch, prison changes a man, and he emerges a madman with little interest in anything except causing horrific "mischief".
** Note that the Joker has just as much contempt for other criminals as he does for law enforcement - no doubt a result of his childhood experiences with Harry and Marv.
* This can even serve to explain the [[ContinuitySnarl continuity errors]] in the fourth film; we already established that ComicBook/TheJoker has a MultipleChoicePast, so what we see as the fourth film could actually be [[UnreliableNarrator a warped retelling of the first two films]], or at least, the fourth film ''did'' happen, [[BroadStrokes but not as shown]]; the contradictions to the first two films are more because we're seeing it through his perspective, and we've already established that [[{{Understatement}} he's not very well in the head]].

[[WMG: Harry and Marv become circus performers after serving their jail sentences following the events of the two films.]]
After surviving everything Kevin did to them, unscathed, they realize they can make a solid living showing off how invincible they are.

[[WMG: Kevin is in a coma]]
* For the beginning of the film, Kevin is alive. But he is nearly killed when Buzz's shelves collapse whilst he climbs them. The rest of the film is Kevin's mind playing out an idealized sequence of events to both amuse and keep him sane: The traps he sets up and the pratfalls the Wet Bandits endure are cartoon-like, which is enough to keep him from going insane from realizing the truth.
** That doesn't explain how Kevin's father found Harry's gold tooth at the end of the first film.
*** Still in a dream. Kevin never wakes up during the film. If you really want to make it bleak, it could be a DyingDream.

[[WMG: Kevin is a distant cousin of [[ScoobyDoo Fred Jones]]]]
* And trap-setting is an almost hereditary talent in their family.

[[WMG: Old Man Marley paid for the toothbrush...]]
* After the clerk gave up chasing Kevin.
** He was there and probably recognized the neighbour kid; and he seems nice enough.

[[WMG: The Wet Bandits have some sort of medical condition, or are on some sort of drugs, that prevents them from fully feeling pain.]]
* It's the only explanation apart from Rule of Funny. They do show some pain, but nothing like the agony they should be feeling, especially in the second movie.

[[WMG: Buzz's story about Old Man Marley...]]
* Wasn't just to scare Kevin. Marley probably called him (or him and his friend[s]) out for being jerks and this was malicious slander. Scaring the crap out of his brother was an added bonus.
** Marley makes mention of this when he speaks to Kevin in the church. Words to the tune of: "There's a lot of stuff going around about me, but none of it's true."

[[WMG: Kevin grows up to be John [=McClane=] from ''Film/DieHard'']]
* I first heard this idea on Cracked.com, don't know if they invented it. Anyway, Kevin and his family eventually enter witness protection and change their names to escape the robbers, since they're determined to kill Kevin in revenge. But Kevin himself (now called John) likes crimefighting and New York so much he returns to the city as an adult to become a police officer.

[[WMG: John Candy's character is Satan.]]
Funny how he suddenly appears right about when Kevin's Mom shouts "If I have to sell my soul to ''The Devil Himself'', I will get home!" He accepts her offer and takes her home, torturing her with a vivid depiction of Hell (ie. trapped in a small room with a polka band) all along the way.
* This theory gets even better when you remember a certain scene from ''Film/PlanesTrainsAndAutomobiles''!

[[WMG: Creator/DonaldTrump was the reason why the [=McCallisters=] got a free hotel suite.]]
At the time the sequel was filmed, Donald (who cameoed in it as well.) was the owner of the Plaza Hotel. He met Kevin only briefly when Kevin asked where the Lobby was. In order for the Concierge to report the stolen credit card, he would have to also report to the owner of the hotel as well as the authorities, whom in turn informed Trump of the situation. When told who the boy looked like he felt bad and ordered the staff who would have initially said no to give Kevin's family the free penthouse suite.

[[WMG: Harry was married and killed his wife before the first film began.]]
Either that or he left her, or perhaps she is also a crook and is already in jail when the films take place. This is why Harry wears a wedding band in the first film.

[[WMG: Marv and Harry are immortal.]]
This would explain how they can survive so many injuries that would kill a normal man.

[[WMG: Kevin was a fan of ''Film/StrawDogs''.]]

[[WMG: Alex in the third film is Kevin's cousin on his mom's side.]]
Karen is Kate's sister.

[[WMG: Harry and Marv used to be plumbers.]]
A friend of mine pointed this out when we noticed the logo on their van: "OK Plumbing and Heating". They were plumbers who worked for a lot of wealthy houses and got greedy (either because they weren't paid well or were paid ''too'' well), leading them to become burglars. Plus, it explains their calling card as "The Wet Bandits".
* It's either that or they stole a van and got themselves someone who could plaster a phony decal on them. Of course, the idea that they were legitimate plumbers who got greedy still makes more sense.
* It seems more plausible that they weren't paid well because if they were paid ''too'' well, then they wouldn't have needed to stoop to thievery and could've bought whatever merchandise they wanted with their own money and still have plenty leftover, especially if they started out as ''legitimate'' plumbers. Whereas if they were underpaid, then their unhappiness with their low pay seems that much more plausible a source of influence behind what drew them to committing crime.

[[WMG: In the Home Alone universe everyone is MadeOfIron.]]
Harry and Marv don't seem surprised to survive what should be deadly injuries in our universe, and don't seem to consider this as a special ability only they have. This also makes Kevin seem like less of a sociopath, if he knew they wouldn't really suffer that much.
* This is surprisingly plausible when you consider [[BigEater how much pizza everyone eats.]] (Kevin wanted--and later got--an entire large pizza for himself, and Buzz ate a whole one before Kevin even had time to reach it!) Humans in this universe likely developed denser, stronger bones and muscles as well as a minor HealingFactor, but have higher caloric intake requirements as a result. This would also explain how Marv was able to launch Harry into the air in the second film--he weighs much more than anyone else, even other humans of this universe!

[[WMG: Uncle Frank is the mastermind behind everything.]]
[[http://www.mandatory.com/2013/07/16/conspiracy-uncle-frank-was-behind-everything-in-home-alone/ Explained in detail here]]. Considering what an asshole and a tightwad he is, it wouldn't be surprising.

[[WMG: Fuller ''isn't'' a bed-wetter.]]
Or at least he hasn't been for some time. It's a lie he lets people believe to make sure that he never has to share a bed.

[[WMG: Kevin is Henry from The Good Son.]]
After the events of the first two films it isn't that out of place to assume social services took Kevin from the [=McCallisters=] because of negligence. His name got changed to protect him from Harry and Marv in the event they get out of jail and look for him. So in The Good Son he lives with a new family but tragically the events of the previous films turned him into a murderous sociopath.

[[WMG: The Wet Bandits are SuperSoldier prototypes.]]
They were in prison before the events of the first film, and the US government conducted hideous human experiments on them as part of a program to develop soldiers who could survive more extreme injuries. Taking a blowtorch to the head or a kerosene explosion point-black is no problem, as they were created to withstand flamethrowers and battlefield explosives. The experiments done to them were torturously painful, resulting in them having a high enough pain threshold to keep going when an ordinary human would've been rendered comatose. They keep escaping from prison because the experiment [[GoneHorriblyRight worked too well]], allowing them to get away by doing things no ordinary human could survive, like crawling through fields of barbed wire or jumping from prison walls several stories high. However, they're still only common thugs with no military training, resulting in them being unable to defeat Kevin because they just rush in and rely on their SuperToughness to survive. This is also why they're prone to [[WhatAnIdiot dumb decisions]] and [[FailedASpotCheck carelessness]]: they know that [[ImplacableMan nothing can stop them]], and are too impatient and impulsive to be more cautious.

[[WMG:Alex from 3 will appear in the Adult Kevin series.]]
But not as another VillainProtagonist. Alex only had one adventure instead of two, he wasn't abandoned for days on end, his siblings' bullying never went as far as the [=McCallister=] kids', and he was recognized by his family and the government for his efforts and even apologized to for being branded a liar by the police, so he most likely would have grown up more well-adjusted. Given that he wanted to grow up to be a cop, maybe he did, and when another Chicago-based trap-maker makes the news as a SerialKiller, Alex recognizes his own EvilCounterpart and requests to be put on the case.
* Is that a fan fic somewhere? This troper would read the hell out of it!

[[WMG:Peter [=McCallister=] is a criminal]]
As convincingly argued [[http://www.reddit.com/r/FanTheories/comments/3xusmc/home_alone_peter_mccallister_is_a_criminal/ here]].

[[WMG:Harry and Marv are either superhumanly tough or on PCP]]
Seriously, many of the traps Kevin sets in the first two films would be lethal or crippling to anyone who doesn't have Wolverine's healing factor from the X-Men: paint cans to the head, bricks to the head, irons to the face, kerosene explosions, falls from 2 stories or more, electrocution, being crushed by heavy objects, and the list goes on. If Harry and Marv were mere mortals, they'd both be dead by the end of the first movie or would be in wheelchairs in the sequel.