6. The Characters Are Just Toys - Smash Bros.
The Smash games were clearly never meant to be taken seriously from a story and lore perspective. The whole point is for players to enjoy their favourite gaming characters being (s)mashed together, without thinking too hard about the rules and plots of the fighters' separate universes.
But where there's a large fanbase, there's rigorous dissection, thorough discussion, and, of course, lots and lots of fan theories - and Smash is no different.
One of the most popular theories is that within each of the Smash games, the characters you play as are just children's toys controlled by an imaginative kid (like The LEGO Movie). It sounds odd, but there's actually evidence to support this, such as boss battles against the giant white Master Hand. A human hand, perhaps?
Eventually, Nintendo legend Satoru Iwata confirmed that the characters are toys in an interview with Time, stating that the games "do not represent the Nintendo characters fighting against one another", and mentioning that the team hotly debated this topic during development:
"They actually represent toys of Nintendo characters getting into an imaginary battle amongst themselves... And frankly that has to do with a very serious debate that we had within the company back then, which was, ‘Is it really okay for Nintendo characters to be hitting other Nintendo characters? Is it okay for Mario to be hitting Pikachu?'”
And no, it's not okay for Mario to be hitting Pikachu. But hitting Kirby? That's okay.