When Super Mario 64 was initially released, all the way back in 1996 for the Nintendo 64, players were disappointed to see that Mario's younger brother Luigi was not a playable character. What's interesting about this, however, was that most people believed that Luigi was part of the game, but he had to be unlocked.
There are actually quite a few people that believed that series creator Shigeru Miyamoto had secretly hinted at Luigi being in Super Mario 64, as a message on Peach's Castle's courtyard read "L is real 2401," leading fans to believe that this was some kind of hidden message, release date, or secret code that needed to be input in order to get the younger Mario brother.
It's been 25 years since Super Mario 64 was released, and a recent leak — which is currently being referred to as the "gigaleak" by players —has finally given us our first look at Luigi, as players have managed to use the leaked source code in order to put together a model of the beloved character.
Shigeru Miyamoto has revealed in the past that they did intend for Luigi to be a playable character in Super Mario 64, but due to memory issues they couldn't actually make this possible. Eventually, Luigi would become playable in Super Mario 64 DS, but that game was released 8 years after the original, and not even for the Nintendo 64.
What's even more interesting about Luigi finally being found in Super Mario 64 is the reaction this event has had, as fans of the beloved classic title are currently freaking out over the fact that they've finally been able to see what the character model would've looked like; 25 years after its release, no less.