Most people will tell you that Super Smash Bros has never been about the story. If anything, it's about arguing over items, character tiers and the reviled "tripping" mechanic. But you have to have a reason for R.O.B. the Robot to get his shit kicked in by Ganondorf, so that's where the Master Hand comes in.
Initially, Master Hand seems like a weird nonsensical boss. It's just a big hand floating in the middle of space. You might be able to say it's Mario's disembodied glove if it that wasn't our plumber duking it out with him right there on the screen.
But it all makes sense when you watch the intro to the original Nintendo 64 Smash Bros. game.
Master Hand is just a representation of a kid playing with his toys. It serves as a believable premise for the game, and at the same time makes sense out of the game's boss. But as The Game Theorists suggest, this revelation has some pretty disturbing implications.
From the setting in the first game, we can assume that the kid is maybe in his tweens -- old enough to read and write, but not old enough to still have plush toys. But then when we get to Melee, the characters are trophies.
Judging by what we know of trophies and Amiibos, these kinds of still figurines are collected by older teens/manchildren. So the kid in the games is getting older, but still plays with toys.
Then we get to Smash Bros. Brawl, which features an intense story mode. Partway through the game, it's revealed that someone else has been pulling Master Hand's strings all along.
Tabuu is nebulous in origin, but it makes more sense when you consider the larger context. If Master Hand is the kid playing with toys, Tabuu is the social "taboo" that wants to hold back an adult from engaging with childish things like spending $115 on a Marth Amiibo.
It seems like a lot to be extrapolating for a kid whose face we never see -- but what if we already know the person controlling the Master Hand? Wouldn't it make sense if the story of Master Hand was the story of the creator of Smash Bros.?
Masahiro Sakurai was still in his twenties when he headed up the original Super Smash Bros. It was the product of a fan, someone who had grown up with Nintendo's characters, someone overjoyed to be able to play with the toybox. As time went on, Smash grew bigger and bigger, and Nintendo kept asking Sakurai to make game after game of the same thing. Whereas Master Hand resembles the creator, the pressure on Sakurai resulted in Crazy Hand, which represents Sakurai's desire to kill his darlings.
Most recently, we had Smash Bros for Wii U and 3DS. Upon defeating Master Hand in a high difficulty setting, the Master Core emerges. A whirlwhind battle follows, but at the end, Master Core gives up and just lets you beat it to death.
That's Sakurai, at his core, laying down and giving up. He knows that the franchise will slowly drive him insane, but he has no other choice. It's either this or let his creation be taken over by someone else, letting someone else be Master Hand.
Okay, that was a bit heavy on the metaphors, so let's go out with science.
It's not news: People are still playing Skyrim. At this very moment, thousands of people are exploring that mountainous corner of Tamriel, adding to their ever-growing hoard of dragon bones and cheese wheels. Almost from the very start, fans have been mystified with one thing in particular: The bug jars.
Scattered across the land of Skyrim are five glass jars. Inside these jars are five different insects: a butterfly, a torchbug, a dragonfly, a moth and a bee. Each of these five bug jars feature a different set of runes carved into the lid. Over time, fans have dug into the meaning of these jars, their locations and the runes themselves, and have come to the only sane conclusion: These bugs are part of a bizarre and powerful summoning ritual that will bring an end to mankind.
There's way too many details and variations on the story to cover everything here, but one of the most interesting permutations of the theory has to do with a huge transmutation circle across the entire map of Skyrim. Cue the classic Conspiracy Photoshop:
The five major cities of Skyrim make a pentagon. Inside that pentagon is yet another pentagon, made up of the three dragon sanctuaries, the Dwemer ruin Mzinchaleft and the Tower Stone. In the middle of this miles-wide transmutation circle is a shrine to Talos. Supposedly the ritual involves killing all the dragons, placing the bugs in their corresponding cities (as evidenced by their runes) and then activating the Tower Stone. After that, the "Promised Day" would come, along with the apocalypse, presumably followed by the events of Kirby 64.
This all sounds pretty improbably and yeah, the internet might be looking a little too hard at some bug jars -- but remember, this is the same world in which all of the dwarves vanished without a trace. Bethesda has always been about filling their world to the brim with meticulous details that no one would notice, like the Thieves Guild markings on every single house in Skyrim. When it comes to these games, anything is possible, up to and including the world being destroyed by a moth.