Wario Land 64

Wario Land 64 is the supposed first prototype build of Super Mario 64, excluding Super Mario FX. The story is that Nintendo didn't want to tarnish Mario's reputation if the first 3D platformer flopped, so Wario was going to be used instead. After the game was proven to be successful with test audiences, they used that as a sign that this wouldn't ruin Mario, so they went and made Super Mario 64. Information on Wario Land 64 is scarce, but several sources have corroborated its existence.

Speculation
Wario Land 64 is speculated to be, as mentioned before, the earliest version of Nintendo's Super Mario 64, which is even older than the July 29th, 1995 build. If Wario Land 64 is real, then the infamous 1995 build was not the first version, and was modified to become Super Mario 64 after Wario Land 64 proved that 3D platformers would work. If one is also to believe that Super Mario 64 was initially sold to Nintendo by an unknown Japanese organization, Wario Land 64 may have come before this, as no reports mention the Personalization A.I. in this build of the game.

Reports

 * Everything in this section should be taken with a grain of salt. These are all unverified claims.

Developer Claim
"I'm sure most people are now aware of the fact that every single copy of Super Mario 64, from '96 onwards is personalized, strictly to appeal to the pleasures of whoever possesses it. Very well, one of the most common occurrences lately in these personalized copies is the appearance of a mysterious anomaly known as "The Wario Apparition". I am here to explain what it is, and why it's there.

''Noone knows where the original build came from, all it was known to employees was that Nintendo wanted to use it to create the first, big 3D platformer. The jump from 2D to 3D was incredibly hard for the company, and thus, they decided, that their first game would not be shown to test audiences and would not be a Mario game, rather a Wario game, instead, as they feared that if the game failed, Mario would be associated with its failure, essentially ruining his image. And so, Nintendo decided to make Wario Land 64, marketing it as a sequel to 1994's Wario Land.''

The game would function as any Wario Land game would: it would have the shoulder bash, harsh movements, and of course, the ability to gather power-ups via being damaged by enemies.

''One of these enemies was the Ghost Spider, that, after the game proved to be successful and was changed from a Wario game to a Mario game, was reused in Wario Land 2 (1998) and onwards. If Wario clashed with the Ghost Spider, he would turn into a ghost, his body would dissolve, and his head would start growing drastically. With that, he would be able to essentially roam the level as an invincible giant head, eating any enemy who dared to cross his path. Sound familiar? There was also a multiplayer mode planned, one where two players could duke it out in an arena using certain power-ups, including the Ghost Spider's abiliry.''

''As mentioned before, after the game proved to be successful to test audiences, most content was reskinned and removed to make it look more like a Mario game. However, the A.I kept most of the content from Wario Land 64, using it to personalize the game. Soon, in Spaceworld '95, the game would be revealed, and played. The devs began getting paranoid, trying to find a way to remove all of the Wario Land 64 content from it, and all of the content from before it was sold to Nintendo. And so, the devs found a way to conjoin every single bit of content they didn't want and throw it out. When it mashed together, unknowingly, they created the Wario Apparition. The reason it causes hallucinations and stroke-like effects for the players who see it is largely unknown as of now, but it is theorized that it has something to do with whatever the game was supposed to be before it was even inherited by Nintendo. All that is known is that the Apparition's inner behaviors are practically an enigma. It is an incredibly unpredictable being, and if it contains whatever cursed content from the game before it was sold to Nintendo it... Let's just say that wouldn't be favorable at all."''

Guidebook
Several images of the supposed guidebook of the game have been leaked online. It was shared by a user who claims that he sometimes gets sent E-Mails with pictures of the guide. At the moment, only two images have been shared. The first image contains the story of the game. It's about Wario trying to recover the power of his castle that was stolen by Captain Syrup by obtaining every Power Star, referred to as golden stars, inside the castle. The second image confirms that there was a multiplayer mode planned for the game, with the second player intended to be Waluigi. Therefore, it would've marked his debut as a character in the Mario franchise. Waluigi's character model and the concept were probably picked up and reused for Mario Tennis. The guidebook appears to have some grammar and spelling mistakes, meaning it was likely an early draft.

Wario's Castle Description
It is unknown where this originated, but a detailed description of Wario's Castle in Wario Land 64 had been released at some point in time. It was an early version of Princess Peach's Castle, more closely resembling that of the infamous 1995 build. The outside is mainly colored dark grey, having yellow where red was, and less cartoony windows with purple accents. Notably, the Princess Peach stained glass is replaced with that of a giant W, signifying Wario's ownership of the castle, but it also appears shattered. The sky itself appears to be stormy, being dark grey and full of clouds. The Castle Grounds appears to have "died", being smaller, with black leafless trees, fitting the gloomier tone. There was also reportedly a door underneath the waterfall that would lead to a dungeon area, either the Castle Dungeon, Horror Dungeon or one of the Wario Land 64-exclusive unused levels. The interior's design was presumably the same as beta builds, just with different textures, having gold walls and symbols referencing Wario on them, likely due to his greed and egotistical nature. Several portraits of Wario, money, and garlic also appear, as well as the paintings leading to the regular levels. Notably, some of them are torn and graffitied. Only one floor is known to exist in Wario Land 64, though more may have been planned. It is believed that Wario's Castle was wrecked due to Captain Syrup's invasion as the story summary of the guidebook explains, causing the irregularly dark appearance of some of the castle.